My Headlights Stay Up After Adding Headlight Relays

[juddev]

Finally decided to do 12ga wired headlight relays so I could use higher wattage bulbs in my Hella E-Code Headlights and now my headlights do not go down, I am sure that I am forgetting something but so far I can't seem to think of what?

What I have done so far:

Amico 2 x H4 9003 Ceramic Wire Wiring Headlight Harness Sockets for Car Headlight $6.06

Amazon.com: Amico 2 x H4 9003 Ceramic Wire Wiring Headlight Harness Sockets for Car Headlight: Automotive

(2) HELLA 003510267 Dual 87 40 Amp 12-36V Heavy Duty Mini SPST Relay with Bracket $2.03 Each

http://www.amazon.com/gp/product/B000VUAJN2/ref=oh_details_o01_s01_i01?ie=UTF8&psc=1

10Ga Red wire From alternator Positive terminal to Term 30 on both relays (about 4 feet each)

10 GA wire Black From Ground hole on Alternator to term 85 on both relays (about 4 feet each)

12 GA Wire Brown from Low beam relay terminal 87 to pass headlight low beam wire

12GA wire Brown from low beam relay second 87 terminal to drivers headlight low beam wire

12GA wire Green from High Beam relay terminal 87 to Pass headlight high beam wire

12GA Wire Green from High Beam relay second terminal 87 to drivers headlight high beam wire

12GA wire Black from NEW Pass headlight socket Ground wire to Chassis Ground in front of battery

12GA wire Black from NEW Drivers headlight socket ground to Chassis ground in front of battery

Cut original brown wire from old drivers headlight socket and ran it to terminal 86 on low beam relay as the trigger

Cut original green wire from old drivers headlight socket and ran it to terminal 86 on the High beam relay as the trigger

I did not use the original headlight ground wire and just cut the old headlight sockets off.

Can anyone tell me where I went wrong?

Do I need the old Ground wire hooked up somewhere?

BTW the Headlights have never been this bright before (I still have the original 55/65 Hella bulbs in)

[wws944]

Check out the schematics in the 1990 FSM (e.g., sections 8A-100 and 8A-102). Up until mid 1990, the Reatta had one relay between the headlight switch and the headlights for hi/lo beam switching. In later 1990 cars (and '91s) they inserted a second relay to route high current around the headlight switch.

The thing to look for is the yellow wire that runs over to the headlight motor module. It looks like it needs to be rewired as well.

I suspect that you will want to rewire the relays to mimic the late 1990 version. That is, wire them in series so that the first one is for headlight on/off and the second one is for high/low beam. The yellow connection connects between the two.

This is interesting to me because I also have Hella E-code lights, and would like to do a similar mod to my car. However my car is a late '90 and already has the additional relay. So I have not really pursued it yet.

[wws944]

Hmm. Basically the headlight module needs to sense, via the yellow wire, both when voltage is applied via the relay and when the lights are off. In the latter case it seems like it leaks a small bit of current through whichever half of the bulb is selected by the high beam switch. Rather than rewiring your new relay setup, I wonder if there is some alternative using diodes...

Two somewhat related questions:

- After installing the Hellas, did you have a clearance problem between the headlight connector and the headlight mounting bracket on the drivers side, when the lights are rotating? Mine just barely touched, but was enough to ruin a couple of H4 bulbs before I figured out what was going on. I solved the problem by making a small adapter harness using a thinner right-angle socket (Dorman #84790) and a male connector that I bought on ebay for a couple of bucks. Passenger side was fine.

- Where did you mount the relays?

[juddev]

Update: the headlights go down if I have the fog/driving lights on.

My Reatta is a 89

I mounted the relays on the front of the relay center cover.

I have no clearance issues with the sockets that I have noticed.

[Guest Mc_Reatta]

You have lost the ability of the headlight module to ground itself thru a headlight filament when headlights are turned off.

What exactly is meant by "Ground hole" in the following statement?

10 GA wire Black From Ground hole on Alternator to term 85 on both relays

[juddev]

The ground hole is the hole on the back of the alternator which normally doesn't have a bolt inserted but can be used as a ground point (as far as I know)

[Guest Mc_Reatta]

It's raining with thunder and lightning here at the moment, so I can't go look at this ground point location your talking about.

I'd suggest you move that connection to another location on the engine block to see if that makes a difference.

[Ronnie]

It is fairly well known that the headlights will not retract when a headlamp is burned out. The way you have changed the wiring to reduce the load on the headlight switch is telling the headlight module the same thing as it would see with a headlamp burned out. You will have to make changes to satisfy the headlight module. I'm not able to follow all the changes you provided in your original post so I can't recommend exactly what you need to do.

[2seater]

I am curious as to the resolution to this issue. I have had two headlight switch failures in the last six months and suspect power through the switch to be a contributor. It looks like in simplest form, a relay could be added right at the headlight switch to reroute power around the outside of the switch, even more basic than the factory upgrade. The most effective as far as reducing voltage drop is detailed above. It looks like the only missing link is rerouting the yellow module sensing wire and I wonder if this was effective?

[wws944]

I am curious as to the resolution to this issue. I have had two headlight switch failures in the last six months and suspect power through the switch to be a contributor. It looks like in simplest form, a relay could be added right at the headlight switch to reroute power around the outside of the switch, even more basic than the factory upgrade. The most effective as far as reducing voltage drop is detailed above. It looks like the only missing link is rerouting the yellow module sensing wire and I wonder if this was effective?

Buick added a relay midway through the 1990 production. Schematic of both before and after is in the 1990 FSM. The factory relay is to the left of the drivers side console fuse block - zip tied to that black cable housing:

Electrically, they simply added the new relay in series between the headlight switch and the high/low beam relay. (Compare 1990 FSM page 8A-100-2 with page 8A-100-6.) Didn't touch the yellow sense wire.

Edited August 17, 2013 by wws944
FSM reference (see edit history)

[padgett]

I suspect what you need is a resistor to match the stock low beam which was 37W stock and I have 55W (Silverstars) that work just fine. I would expect a 3.3-4.7 ohm resister, the same as for the SIR would work. Might want to use a pot and come down from the high side to find the actual. A steering diode migh not be amis either. I am surprised the relay coil current would not be enough.

[wws944]

Padgett - the way the headlight door module sensing seems to work, the yellow wire really needs to be on the 'bulb' side of the relays. I think there are three states - a.) headlight switch on - 12v on the wire, b.) headlight switch off - detects that there is continuity to ground through both headlight filaments, and c.) headlights switch off, no continuity through at least one of the filaments - detecting that a bulb has burned out. With the relay harness that juddev made, the module only detects states a and c. This indicates to me that the yellow wire to the headlight door must be connected to the high current filament side of the relays. It also may suggest that the best way to do it in a Reatta is to wire the relays in series. That is, use a headlight on/off relay, followed by a hi/lo relay - rather than wiring them as hi beam on/off and low beam on/off.

My implied suggestion in post #10 is that if one were simply interested in bypassing the high current path around the headlight switch, it might be easiest to simply follow what the factory did in the later 1990 (and 1991) cars. Hardest part would be removing the console for access to the back of the fuse block. Same mod should work for '88-'89 cars too.

Even though the stock Guide H6054s draw 35w on low beam, they are actually rated to draw 65w on high beam. So the wiring, and I'm guessing the headlight door modules sensing circuitry, take at least this range of values into account.

I would think '87-'88 Fiero guys would have already addressed this issue - since don't their cars use the same headlight door module? But googling around a bit, I really don't see any good links on it.

[2seater]

I have looked at the factory diagrams and I think I understand what needs to be done to do the factory upgrade, which looks to include a small upgrade in power to the lights as well as reducing load on the switch. I am considering doing a more extensive upgrade, with direct power to the headlights, similar to what was detailed by the OP. It looks like the yellow wire to the module must have a connection to the output side of the relay so it "sees" the headlight filament. Adding one or more relays closer to the lights is really redundant but reducing voltage drop, etc. through the factory wiring is what we are after, yes? My lights are out of commission right now so I don't have a good way to see what the actual factory voltage delivery is.

edit: I see there was an additional post and I will say, at least on mine, the circuit panel slides out of the console after removing the four mounting screws/expanders on the sides, so access isn't too bad.

Edited August 18, 2013 by 2seater (see edit history)

[wws944]

Ok, I just went and measured mine. With stock 60/55w H4 bulbs, voltage between the high side of the low beam filament and ground (alternator case) was about 12.8v at idle. Revving the engine it would get almost to 12.9v. On high beam, voltage was about 12.03v at idle, and got up to maybe 12.10v with some RPM. I only measured the drivers side - since it was easy to do thanks to the little extension cable I made for my Hella housing.

Note that my car is a late '90 with the factory relay mod. It would be interesting to see the same measurements on an earlier car.

ED10 read 13.6-13.7v during the tests. This indicates to me that there is definitely some to be gained in any case with a better relay harness setup - as the OP experienced. Downside would be shorter bulb life.

[2seater]

Thank you for that information. I'm sure mine would be worse with the 80/100 Hella's I am using. I should really have known better, so no need to kick me, I'm busy doing it myself. It would have been nice if the standard hi-low relay would have been under the hood, but that's not the way it is. In any case, it seems even the factory upgrade would be very marginal. It looks like the factory wire size to the left headlight is only equivalent to 16ga. I see why the two hi and lo relays were used, because it appears to be straightforward to trip with the hi and lo beam wiring. One enable relay and a single hi-lo relay also works, which essentially mimics what is happening in the late model upgrade already inside the car, redundant really, but should work okay. The question I guess I still have is what to trip the enable relay with? It would seem to be direct power from the headlight switch. Anything like that available under the hood? Yellow module wire connected to the input of the hi-low? I'm probably plowing old ground and apologize if I am.

[wws944]

Thank you for that information. I'm sure mine would be worse with the 80/100 Hella's I am using. I should really have known better, so no need to kick me, I'm busy doing it myself.

Ok, I won't.

It would have been nice if the standard hi-low relay would have been under the hood, but that's not the way it is. In any case, it seems even the factory upgrade would be very marginal. It looks like the factory wire size to the left headlight is only equivalent to 16ga. I see why the two hi and lo relays were used, because it appears to be straightforward to trip with the hi and lo beam wiring. One enable relay and a single hi-lo relay also works, which essentially mimics what is happening in the late model upgrade already inside the car, redundant really, but should work okay. The question I guess I still have is what to trip the enable relay with? It would seem to be direct power from the headlight switch. Anything like that available under the hood? Yellow module wire connected to the input of the hi-low?

If one hooks the two relays in series, like the factory mod does, the yellow wire connects between the two. So it is hot when the headlights are on, and not when the headlights are off. The second aspect of it is that when the headlights are off, the headlight door module must be sending some small leakage current through the filaments to detect a bad bulb. The factory mod is easy because all the needed wires are readily available by the fuse and relay blocks at the front of the console.

I am now thinking if I were to build a relay harness, I would do it similar to the factory method. Since I abhor cutting up my factory wiring, I would probably pull the pin for the yellow wire out of the connector shell by the headlight door module and tape it off. Then run a new yellow wire from the headlight door module to a point between the two relays. That way the mod would be totally reversible back to stock if a better way to do it became apparent in the future.

I'm probably plowing old ground and apologize if I am.

I don't think we are plowing old ground. There is nothing in the archives of this group on it, at least.

[Ronnie]

A tutorial on how to do this would be nice. It might save a lot of headlight switches that are getting hard to come by.

[2seater]

Thanks a bunch. That is what I thought was the best way. I also though about pulling the connector but some are pull to seat complicating that procedure. Not sure about these. I'm thinking you mean the giant connector on the fender just to the rear of the relay center? It looks like there is a splice before the module as there are two yellow inputs to the module but only one wire feeding them both. Since the original will remain from the old style wiring, I will only be duplicating the hi-low relay in a second location. I don't like a bunch of extra splices either, but some will be required. Both headlight sockets are showing heat damage at the ground connection, particularly the right side, which has extra voltage drop due to the harness design. I don't remember seeing a circuit breaker in the OP, but will be included in this one. The factory mod would be the easiest upgrade, but I don't like the light ga. wiring feeding 200 watts of headlight. Now that I think about it, it would also be a factory upgrade "enhancement" to replace the factory wires with heavier gauge gauge to the headlights with a separate harness? Still need to connect the yellow wire to the low beam splice where they split up front? It would be little more work than pulling a headlight activation wire to the enable relay? I greatly appreciate the insight and info. Much to think about.

[DAVES89]

Hi Hal remember I have a completely stock '90. Also have an extra '90 switch. Bring your car over one night and we can get this done. Or I can come to yours with the car...

[juddev]

I have now used the new harnesses for 2 months now, as long as I have the fog lights switched on (I normally do anyway) and I turn off the headlights before I turn off the car (otherwise the headlight doors stay open) the lights work fine, they just stay on for 3-4 seconds after the headlight doors close.

As I stated before....I will never go back to even the 55w Hella lights as the 80w lights make it a pleasure to drive at night and at no time has anyone flashed me thinking I had the brights on. Considering the price of silverstars and the $7 price of the Hella 80/100's bulbs, this conversion is well worth it for safety reasons alone....IMHO

[DAVES89]

A tutorial on how to do this would be nice. It might save a lot of headlight switches that are getting hard to come by.

I agree with that. I am sitting on 3-88/89 and 2-90 switches just because of that fear...

[2seater]

I would be happy to write up what I eventually decide to do. I am leaning toward doing the factory relay upgrade and also run two new 12ga. wires to the headlights from the Hi-Lo relay, probably in parallel with the existing ones. I am guessing that the yellow wire will still function as originally intended. Edit: Oops, I should look at the diagram and not from memory. Since I do not presently have the upgrade, I will need to relocate the yellow wire to match the updated wiring schematic.

Dave: I will call as soon as I have a chance.

Edited August 19, 2013 by 2seater (see edit history)

[wws944]

The factory mod seems to do the following:

1.) The yellow wire that goes from C7 on the headlight switch, through C201, and tees off to the HI-LO relay and headlight door module (via splice S255), is replaced with a purple wire through C201 to trigger the new Headlight relay. No splice to the headlight module.

2.) New (2nd) orange wire from the Hi-LO circuit breaker 21 in the fuse block to the unswitched side of the new Headlight relay.

3.) Yellow wire now connects to the switched side of the new Headlight relay, instead of coming from the headlight switch. Splice S255 continues to tee off to the headlight door module.

4.) New black ground wire from relay coil to splice S220.

Conceptually, it looks like a pretty easy mod.

To increase the wire size of the high current path for higher than stock power H4s is a little more of a chore. It would require fishing two new wires from the HI-LO relay to parallel the light green and tan wires out through the firewall to the front of the car. Also the new orange wire between the fuse block circuit breaker and new Headlight relay. And finally the yellow wire between the two relays would need to be upgraded (but not the spliced out yellow wire out to the headlight door module.) Then don't forget the black wires from the bulb filaments to ground.

One unknown that I was thinking about with high power bulbs was if the headlight door module could correctly determine if one or both of the filaments were burned out. But since you have already been using 80/100 bulbs, and they have been ok in that respect, the answer seems to be yes.

Edited August 19, 2013 by wws944 (see edit history)

[Guest Mc_Reatta]

I have given a lot of thought to this undertaking, and have a design in mind on how I will attempt it.

My ground rules for implementation are to keep the car itself stock and everything has to plug and play, and all high current wire runs need to be sourced from the battery and kept as short as practical.

How I plan to implement once the summer heat has calmed down and the mosquito population has subsided is to use a headlight socket to supply the signals for commanding the high/low beam headlights on bringing it to a black box mounted to some existing holes on the frame rail beneath the battery.

The black box will contain two 40 amp relays (one each for high / low beams, the 20 amp circuit breaker (upgradeable) and an emergency switch to force the low beams on should any component inside the car fail not allowing the low beams to function. Just crank up the lights manually if needed, flip the switch on and you will have low beams so you can get home in a pinch.

The current 20 amp circuit breaker is moved from the fuse panel to the black box and replaced with a 5 amp fuse thus limiting all of the circuitry of the switch and other components inside to 5 amps max to prolong their life and keep the wiring from smoking if something shorts out. The prongs on a standard fuse need to be trimmed down to fit in the receptacle for the circuit breaker, but that's what Dremels are for.

The rest of the wiring is straightforward using proper gauge for the current load from the battery connection by the overflow bottle thru the relays to new headlight connectors for each side.

Grounds for the relay coils and the headlamps are connected to the ground point on the radiator rail in front of the battery. The headlight yellow sense wire will be drained to ground thru the coil of the new headlight relays which should allow proper retracting of the lights when off. You will lose the function of that circuit to tell you the headlights have burned out, but that isn't a big loss in my mind.

The new wires are sheathed and routed carefully to the headlights so they are safe from strain and interference as the lights raise and lower, and existing wires tucked safely out of the way too.

The relays and headlight sockets are available from sources like Amazon (go thru Reatta store if you like) Other parts can be scrounged from wherever, like pick and pulls, surplus etc.

I recommend 14 gauge wire min to supply power and ground to the lamps which is adequate for up to 100 watt bulbs. If you feel the need, upgrade to 12 gauge and bump the circuit breaker to 30 amps.

I will be doing this upgrade to all my 89's and would recommend to 90s owners who want to run higher than stock wattage bulbs.

Edited August 19, 2013 by Mc_Reatta (see edit history)

[Guest Mc_Reatta]

For those looking at this type of mod, the yellow sense wire to the headlight door module does not have to go between the headlight relay and the high / low beam relay.

It can be connected to either positive wire to the headlights (light green or tan) anywhere along its run. I'd chose the low beam tan wire though since knowing they have burned out is more important than the highs in my opinion.

I'm not sure if the module is sensitive enough to know if one bulb has burned out, or both bulbs have to burn out before it keeps the lights up. As wired though, it will show that status for the bulbs last selected whether high or low beam.

If the resistance of the added relay in my design proves to be too high to allow for the headlights to retract, another source of resistance (probably a small light bulb) will be added in parallel to the relay coil to get the module to function properly.

[2seater]

Mc, thanks for adding to the discussion. I too have been debating which way to go. The best voltage drop solution is as you stated and done by the OP, short power runs direct from B+. The factory upgrade is limited to helping the switch and a bit of reduction in voltage drop, all useful. This appears to be a relatively simple change all done inside the cabin. I don't believe it to be adequate for 100w bulbs(even though it has worked for years with an 18ga. feed). I am still investigating the route I will take. I found that splice for the yellow wire in the console but no way to discriminate which way the splice goes so cutting it and reusing it for two jobs is probably out the window. A new wire from the switch to relay is probably the easiest as you mentioned.

[wws944]

For those looking at this type of mod, the yellow sense wire to the headlight door module does not have to go between the headlight relay and the high / low beam relay.

It can be connected to either positive wire to the headlights (light green or tan) anywhere along its run. I'd chose the low beam tan wire though since knowing they have burned out is more important than the highs in my opinion...

Well... Sort of. The yellow wire is how it knows the headlights are on, so it can engage the motors. If you look at Section 8A-102, the headlight door module (can we agree to call it a HDM) actually has two yellow wire inputs - A and C. Splice S117, wherever it is, splits the yellow wire from the console into two wires for the two inputs. So this seems to indicate that the HDM was designed to allow for a quad light configuration. Makes sense since same era Firebirds used the same HDM.

With this in mind, in a totally underhood harness with separate HI and LO beam relays, it seems one could feed a yellow signal from the LO beam filament to Input A, and a separate yellow from the HI beam filament to Input C. (Or vice versa.)

So where is splice S117? FSM says somewhere near the HDM.

[2seater]

No doubt the splice will be where most difficult to work with I keep flip-flopping back and forth and have decided that it just isn't worth the time to do a halfway measure. The best is to have the relays up front and the power feeds as short as possible, as the OP did and Mc has also suggested. The only thing additional I can see that I need from the inside to under hood is a feed from the headlight switch to trip the enable relay and a second relay to switch beams. The FSM shows the yellow wire to low beam filament, but in between relays is factory style and what I will do. I'm thinking the yellow wire connects to that giant connector on the fender, probably hidden by the air filter on stock cars. Still need headlight power to the original hi-lo relay in the console to satisfy the BCM and allow hi-lo switching.

[wws944]

For my little extension cable, I bought a male H4-style plug for a couple of bucks from an ebay vendor. Some Amazon vendors have them too. Just plug it into one of the original headlight sockets to get the correct HI/LO signals for your relays.

[Guest Mc_Reatta]

In an 89, that splice is S255 and is located in the wiring harness behind the left side of IP.

Could also tap in at the diode which is in front of the interior relay center in an 89.

Not worth it in my case.

I do think that the HDM may be very sophisticated at sensing the presence of both lamp filaments which will take some ingenuity to work around if replacing their position in the stock circuit with a relay. That just adds to the challenge.

[wws944]

More on the HDM on a thread I found while googling around. Check out the 2nd Fiero schematic in post #7, and the Firebird schematic in post #32:

Pennock's Fiero Forum - Installing Gen 2 Firebird Headlight motors into Fiero (by masospaghetti)

In both cases, Inputs A and C are connected to the headlight switch. And post #33 describes some subtle differences between modules.

But what the schematics do not show is how the headlight filaments are connected. Maybe Kit or someone else with access to either Fiero or Firebird FSMs could fill us in?

[wws944]

In an 89, that splice is S255 and is located in the wiring harness behind the left side of IP.

Could also tap in at the diode which is in front of the interior relay center in an 89... That just adds to the challenge.

Hmm, I see... They run both yellow wires through the firewall.

So I am guessing a 'no permanent mods' strategy would still be to pick the yellow wire pins out of the (Metripack?) connector that plugs into the HDM for Inputs A and C, and tape them off. Then install two new yellow wires in their place that run to the switched sides of the new relays.

[Guest Mc_Reatta]

Here's the easy way to add in a new SPDT relay underhood to move all the high current load out of the interior wiring and supply power to headlights direct from battery.

This will allow burned out bulb function of HDM to continue to perform normally.

Same hookup for both the high and low beam sides.

If a fail safe switch is wanted to turn lights on even if the internal headlight switch, headlight relay, hi/low beam relay, etc. stops working, just wire a switch capable of at least 10 amps between 3 and 1 on new low beam relay. This will back-feed the BCM and should raise the headlights as well as turning headlights on. If headlights won't raise, you will have to raise them manually.

[2seater]

Not to ignore the detail discussion, but I believe I asked about a direct headlight switch power feed to under the hood, but couldn't see the forest for the trees. The yellow wire IS the power direct from the headlight switch. On the '90 without the upgrade, the yellow wire runs from the headlight switch to supply the power to the hi-lo relay in the console, which comes out as the tan and green wires to the headlights. Along the way from the headlight switch to the relay, s255 taps off the yellow wire and routes it out to the headlight door module. In the upgrade we are discussing, the yellow wire is cut and now becomes the signal to turn the enable relay on, and the end that was cut off becomes the signal wire to the module, connected to the output of the enable relay, yes? Perhaps this is obvious to others that tried to tell me that, and I missed it, or when tracing a circuit over multiple pages, I look where I'm going and forget about where I came from?

As an aside, why on earth would the factory place a splice in a wire run less than 12" from the terminal? If it was at junction where the harness splits, it would make some sense, but in a straight run? On the '90, S255 is 9" from the relay terminal in the console. Very difficult to unwrap the harness to find it inside the console. It would be very simple if connected at the terminal since the relay center slides right out for access to the rear. It seems plain to me that a more efficient way would be to split the wires at the terminal, just like is done at the left headlight socket.

Edit: I found that splice where the yellow splits for the headlight module. It is inside the 1" diameter split loom between the fender and the relay center. It can be accessed by releasing the harness clamp on the fender and pulling it upwards. I also have the giant harness connector that is just to the rear of the relay center unbolted from the fender. Since my engine air intake is not stock, access is probably easier than stock.

Edited August 20, 2013 by 2seater (see edit history)

[Guest Mc_Reatta]

There is no need to do anything to the yellow wire. It is readily available as it is connected to either the light green or tan wire via the high/low beam relay depending on the state of that relay. So using those two wires as the signal sources to activate the new high and low beam relays is the easiest and simplest way to go. By using the normally closed (NC) contacts of the new relays, the bulb filaments are connected to those tan and light green signal wires when switched off thus allowing the HDM to drain to ground thru the bulbs allowing the doors to retract normally.

[wws944]

The HDM looks like it uses Weatherpack or Metripack connectors. With this in mind, a 'no cutting' approach would be to find male and female Weatherpack/Metripack connectors and build them into the new harness. That way one avoid using the yellow wires from the headlight switch, and instead wire the HDM inputs to run to the switched sides of the relays.

[wws944]

There is no need to do anything to the yellow wire. It is readily available as it is connected to either the light green or tan wire via the high/low beam relay depending on the state of that relay. So using those two wires as the signal sources to activate the new high and low beam relays is the easiest and simplest way to go. By using the normally closed (NC) contacts of the new relays, the bulb filaments are connected to those tan and light green signal wires when switched off thus allowing the HDM to drain to ground thru the bulbs allowing the doors to retract normally.

Interesting idea! And would provide the fix for the OPs problem.

[Guest Mc_Reatta]

Simplest way I can figure how to do it ensuring the draining of the yellow wire thru both headlight bulbs has to be preserved to have the doors close. I'm assuming that the doors won't close due to the higher resistance of the new relay that comes into play. If that higher resistance does not prevent the doors from closing when turned off, then things are even simpler with no need to connect the NC relay contact to the tan signal wire. But I'm guessing it will matter.

[2seater]

I will admit upfront that I am a little slow as to what others may take for granted. I must be misunderstanding. If anything is connected to the NC terminal, 87a, and terminal 30 is connected to an unswitched B+, won't that function be active with the power removed? I am having difficulty getting my head around this but I don't see how you can avoid using a power enable relay to feed the beam switching relay, and relocate the yellow wire connection point? The separate hi and low relays would work as well, but the yellow wire still needs to be relocated.

[wws944]

If I catch Mc_Reattas drift, the relay switch is double throw. So instead of leaving the 'off' pole open, route it to the coil wire that goes to the old headlight connector. That way when the lights are off, the HDM can still probe the bulb. (Via the yellow wire back to the console, then back out either the green or tan wire - depending on whether HI or LO was selected.)

Another solution would be to find a 5-pin Metripack connector for the HDM. Two of its pins are Inputs A and C. Two more for +12v (note: each is on its own 15a fuse) for each of the headlight motors, and finally a ground. Just pull the old 5-pin connector. Then wire the new one as part of the new harness that you would be building. I'd bet Jim Finn or Marck could supply some 5-pin connectors. But they are probably easily available locally at FLAPS or dealers.