Fog Lights

[Mr. Anderson]

Ok everybody, I have finally ventured under the hood to check the Fog Lights! As some may remember, my fog lights do not work at all when commanded by the switch on the console. They do, however, work when the anti-theft system is triggered, and they flash just like normal. An odd circumstance, isn't it?

 

I spent the majority of the evening chasing down wires and doing the tests found in the FSM. So far:

 

-I have verified that the Fog Light Switch does indeed work. I bought a new one last year in an attempt to fix this issue.

-Using diagnostics, I can hear the fog light relay clicking on and off. I was skeptical, so I switched with a known working relay (fuel pump) and nothing changed, so I am assuming that the relay is good.

-I have chased the wire from the fog lights back almost all the way to the interior. I know that the purple wire is the hot wire according to the FSM, and it was not reading anything with a test light, voltmeter, or ohmmeter. The ohmmeter showed ∞ which indicates a short somewhere on the circuit. 

 

Now, in the FSM, some of the fog light tests mention hooking a test light to position 1 or 5 in the relay. I had no idea what it was talking about, so I did not test that. My question is: where should I go from here? I have power inside at the fuse block but not outside to the fog lights, and I am just unsure of what I need to do next.

[Guest Corvanti]

Brett, have you tried turning on the parking lights, then trying the fog light switch? i ran my Reatta in the daytime with both on - kinda like DRL's.

 

another "weird" thing i'd check is turn your headlights on and make sure the 'brights" are off. i wouldn't think that would have anything to do with it - with the headlights off, but with various electrical gremlins - who knows? btw, when the fogs are operating correctly, when the brights are applied, the fogs automatically turn off...

[Mr. Anderson]

Kerry, I have tried turning on the parking lights and then the fog light switch, but the fog lights still do not light. I have also tried the brights to make sure they work, and the fog lights won't light no matter the condition.

[Guest Corvanti]

sorry none of that helped.   the other thing i would suggest is checking the ground(s). but you did say the fogs do work when the anti-theft is triggered. i don't have my FSM anymore, but wonder if the pos & neg for the fogs on the anti-theft "splice in" somewhere different down the line than the switch.

 

time for the electronic experts to take over!   they can walk you thru the hooking the test light to position 1 or 5, plus other possible solutions...

 

good luck!!!

[Mr. Anderson]

I have found the solution! I followed the tests in the FSM once I saw that the relay positions were conveniently labeled right on the relay center for me. I was able to make the fog lights work by jumping a paperclip between positions 1 and 4. The test result said that I need to replace the fog light relay. Odd, considering I have already swapped it out and heard it click through diagnostics, but now I can at least start here with a new relay.

[Guest PontiacDude210]

I went through the same thing with my trunk release relay. Heard the relay work, release worked jumped, turned out I had several bad relays in my inventory.

[KDirk]

Keep in mind that hearing the relay click only indicates the coil is pulling in the moving contacts in the relay. If the contact points on either the moving or fixed contacts internally are bad (corroded, mis-aligned, or who knows what) the power will not make it through the relay, despite the audible indication of a functional coil.

Also check and make sure one or more of the female contacts inside the relay center aren't distorted. It may be the jumper you are using is making contact where the "blade" contact(s) on the relay might not be. If these have been spread too wide from previous probing or some other damage, you will need a dental pick or similar implement to re-align them and tighten the fit.

I had a similar problem years ago with a fuse receptacle on one car where the round point probe on a VOM would make good contact (thus showing voltage present on the line side of circuit) but the contact on the load side was spread apart too far to make good contact with one side of the fuse (blade type). Took a while and trying several new known good fuses for me to realize what was wrong. These are the screwball things you run into on older cars that may have had questionable maintenance or repairs done prior to ones's ownership.

KDirk

[Mr. Anderson]

Ok, an update to this:

I replaced the relay and the situation remained the same.

I checked to see where the hot sides of the relay were. The top and left side had power. (Position 1 and 5) This is correct according to the FSM.

The BCM suddenly began to allow the fog lights to flash on and off via diagnostic mode. The relay also clicks when this happens.

BUT, the fog lights cannot be operated from the console switch, which is odd because the switch is showing as good from BCM diagnostics when it switches from HI to LO.

So, what should I try to check next? I'm not sure that this is a wiring problem or a connection problem.

[KDirk]

Let me recap here to be sure I'm getting the whole picture:

1. Diagnostics shows the fog light switch cycling.

2. Diagnostics can override the fog light relay and turn it (and in turn the lights) on and off.

3. You have tested known working relays in the spot for the fog lamp relay with no change.

If all the above are correct I am having a hard time figuring out how the fog lights won't operate. The BCM is seeing the input from the console fog light switch, and is operating the output to the relay coil (as evidenced by being able to cycle the lights from BCM override) so this seems to rule out wiring, a faulty switch, a faulty relay or a faulty relay socket. The only thing left is that somehow the BCM is not acting internally on the fog lamps switch input (when active) by triggering the fog lamp relay output in response. If that is the issue, it is a BCM or PROM problem. Hard to believe that would happen but in light of your previous problems with the BCM and EEPROM now I'm wondering.

Is the option content for the car programmed correctly?

Here are the correct values for a 1991 Reatta configured for US (not Canadian) use:

Option 1 (BS06): 146

Option 2 (BS07): 228

Make sure these values are correct. If not that may explain it, and these values need to be entered and saved first. This can be done in-car from diagnostics mode. If they are both correct then it will be time for further troublshooting.

KDirk

[Mr. Anderson]

The values are not correct in my car. I know that TEMP will alter the value, but how do I save the new number? Also, is this done in the override section or the BCM data section?

Edit: The new values solved the issue.

I figured out how to save values via section 8D in the FSM. For others looking, you hold HTR and DEF for 3 seconds (heater and defrost).

Edited June 29, 2015 by Mr. Anderson (see edit history)

[KDirk]

Hey, I should have mentioned how to save new values but was rushed when I made that post. Glad you figured it out and it solved the problem. I suspect your option programming got messed up during the whole odometer ordeal as that is stored in the same EEPROM.

While I'm thinking about it, are you interested in selling your extra console foglamp switch since it is a spare now? The one in my 'vert is a bit rough and the Camaro used a similar one I found but has orange (not blue-green) illumination.

KDirk

[Mr. Anderson]

While I'm thinking about it, are you interested in selling your extra console foglamp switch since it is a spare now? The one in my 'vert is a bit rough and the Camaro used a similar one I found but has orange (not blue-green) illumination.

KDirk

 

Kevin, if I can find it, then yes. It didn't look the best when I removed it, but I think it still worked and illuminated correctly. I just hope that none of the plastic keepers didn't break during removal.

 

I will say that if it isn't in good shape, you might want to check rock auto for one. Every now and then they get some in stock. That is where I got my new one and it works perfectly.

[KDirk]

Ok, PM me if you do find it. If it is better condition than what I have I may be interested. Otherwise, I will try to make a good one out of the existing one and the Camaro one I picked up.

KDirk