Guest reattasteve Posted October 31, 2007 Share Posted October 31, 2007 When I drove the 90 Reatta tonight the dimmer switch wouldn't switch the lights from bright to dim. I did not hear the click either as I pulled on the smart stick. The dash light did reflect a change as did the fog lamps go out when the bright indicator went on. Is my problem in the steering column, smart stick or where? Ideas? Thanks, Steve Link to comment Share on other sites More sharing options...
Jim Posted October 31, 2007 Share Posted October 31, 2007 The dimmer switch is mounted near the bottom of the column and is held to the column by a couple of screws. A rod comes down from the arm to operate the switch. Your switch could need adjusting or be bad. I do have a good one if you need it and can be reached at jfinn@cpinternet.com Link to comment Share on other sites More sharing options...
Barney Eaton Posted October 31, 2007 Share Posted October 31, 2007 Looking at the headlight schematic in the manual (8A-100-2)The switch in the turn signal lever grounds a terminal on the BCM.I believe the secret here is the indicator on the dash is changing...that tells me the turn signal switch is working.The BCM then grounds the coil in the HI-LO relay and switches the lights.I believe you have a bad "E" relay in the interior relay center. That is located on the Right side of the console. Link to comment Share on other sites More sharing options...
Guest reattasteve Posted October 31, 2007 Share Posted October 31, 2007 Thanks for the quick responses, it looks like I'll be taking the hush panels down and looking to reset(reposition) the dimmer switch or replace it. The quick fix relay I switched out and was not the problem. Tomorrows project. The dealer quoted $40 for the new switch. Thanks again, Steve Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 1, 2007 Share Posted November 1, 2007 I've gotten myself into a real mess, I had to drop the steering column down to remove the switch, lots of trim pieces to take apart. More work than I thought. I replaced the switch but now the rod has come disconnected from the multi-function stick, which means I need to remove the steering wheel and get at the upper connection to the dimmer switch rod. I need a wheel puller and some help on how to get it done. I've got the service manual which helps some. Right now I'm headed to the golf course for some therapy, Thanks for your help, Steve Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 2, 2007 Share Posted November 2, 2007 The switch I got from the dealer won't work, it does not match the electrical connections so I need the right one. I've sent Jim Finn an email for the one he has. The rod I had trouble with just rests against the smart stick so after some finagaling I got it to position properly. But the wrong switch is still the problem to be fixed. Soon I hope, by the way, shot a 79 at the golf course. My best round of this year. Thanks, Steve Link to comment Share on other sites More sharing options...
Guest DAVESWF Posted November 2, 2007 Share Posted November 2, 2007 No help with your problem -- rather, this concerns your other HOBBY. NICE ROUND ! I left WI (for FL) a week ago because it was getting too cold for golf, but it looks like you have been having nice weather this week . Hope the nice weather continues. Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 2, 2007 Share Posted November 2, 2007 I bought the right switch and installed it. The problem remains, now what? I'll try a new relay next, but I have already switched it with one next to it in the fuse box. They are the same number so I'm not sure I'm closing in on the problem. I am getting a little frustrated, I need more therapy. Thanks, Steve Link to comment Share on other sites More sharing options...
Barney Eaton Posted November 2, 2007 Share Posted November 2, 2007 Sorry you changed the switch...if you read my reply, the high beam indicator on the dash would not come on unless the switch was working. There are some slight differences between what the service manual call early Reattas and late Reattas.what is the vin number of your car.....unfortunately the manual does not give a clue what is early and late. Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 3, 2007 Share Posted November 3, 2007 1g4ec13c5lb901202 Hi Barney, When I read your reply I tried to look at the relay which I did trade with the one next to it. No change! So where do I go then, thinking that the smart stick did not have a solid click feel to it when I dimmed the lights. That's why I decided to change out the switch. So today I also bought a new relay, aftermarket from Bumper to Bumper. Still not working yet. I am stuck right now as to what's next. Do you think I need a new BCM for this fix? Thanks for your help, Steve Link to comment Share on other sites More sharing options...
padgett Posted November 3, 2007 Share Posted November 3, 2007 Am assuming the the low beams stay on when you try to go to brights, if they go out, you have a different problem.1) Either buy the service manual or download it from Reatta.net.2) Look in section 8A-100 (in file 8A08 if downloaded)3) No Reatta came with the twilight sentinel. The circuit is similar for both and goes through several relays. Breaker 21 provides power but if you are getting low beams the only one of interest is the hi-lo relay which is controlled by the BCM. 4) Are your fog lights working properly ? If not look to fuse 10 (parking lights). 5) If they are then you are left with the relay, the relay socket, the the wire to the BCM, the hot lead, the BCM , the HI beam socket, the HI beam filaments or the wiring from the relay to the HI beams.6) To start, turn the headlights on and remove the relay - headlights should go out but parking lights stay on (if not, that was the wrong relay).7) Jumper pin 1 (yellow wire) to pin 4 (light green). Did the HI beams come on ? 8) Jumper pin 1 to pin 3 (tan). Did the LO beams come on ?9) If both came on then the problem is in the primary circuit of the relay. (coil, BCM, wiring, socket, power)10) If only the LO beams came on, then the problem is in the secondary wiring to the HI beams (relay socket, wiring to lights, light sockets, filaments.11) if the primary circuit is the problem , check the relay socket for 12v on pin 5 (orange & hot all of the time)12) If have 12v and the relay is good then the problem is in the socket, the wire to the BCM, the BCM connector, or the BCM. Link to comment Share on other sites More sharing options...
Barney Eaton Posted November 3, 2007 Share Posted November 3, 2007 If your vehicle is "early" according to the manual.The 12V from the headlight switch, goes directly to the HI-LO relay. If you have an early and the relay is good, you probably need a BCM (try Jim Finn)If you Reatta is "late" there is another relay in the system. It is called the "headlight relay" and is located in the front of the console. Link to comment Share on other sites More sharing options...
manikmekanik Posted November 3, 2007 Share Posted November 3, 2007 Alright! A 'nuther cheezehead! Only an hour away!Have you met Vincent Vega, yet? He's just south of Mad-town.I'm down by Lake Geneva, and have a shop, manuals, and diagnostic experience available to assist Reatta owners. I recently have taken a few columns out, and have a parts column you can get pieces from. With 3 parts cars, we can find most anything you need to repair/restore your Reatta. I also have a whole box of relays I got from Jim Finn awhile back.You're in the right place for technical advice, and some of the best advisors have already chimed-in to help you diagnose your hi-lo problem. Best of luck in your endeavour! Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 3, 2007 Share Posted November 3, 2007 I think I have it figured out......This is what I should have done first. Get the service manual out, look for codes, b420...hi low problem (showed up right away), do the diagnostics which lead me to disconnect BCM and if the lights dim....replace BCM. Hard to belive thats the fix for a simple circuit as the hi/lo beams. Why control that with a computer? What engineer needed that to keep his job? Where do I go for a BCM? Do I send it somewhere for a fix? Doesn't it record odometer readings? Thanks again for all your input, I eagerly await your help with my next move. Steve Link to comment Share on other sites More sharing options...
Barney Eaton Posted November 4, 2007 Share Posted November 4, 2007 You can contact Jim Finn or get a BCM from a Riviera.The mileage is on removable PROM, Link to comment Share on other sites More sharing options...
Guest reattasteve Posted November 11, 2007 Share Posted November 11, 2007 One of the nicest 90 Reatta's is now fixed. Yesterday a replacement BCM came from Jim Finn and is now installed and working correctly. Thanks to all who had input to my problems and support for getting the car back up and running. This is a wonderful site for support for these complicated machines. Thank you all! Steve Link to comment Share on other sites More sharing options...
Guest reattajack Posted November 14, 2007 Share Posted November 14, 2007 the ecm prom records mileage...bcm does'nt need to be changed out in any way...bcm has the red socket connector, ecm has orange socket.. Link to comment Share on other sites More sharing options...
DAVES89 Posted January 13, 2021 Share Posted January 13, 2021 On 11/3/2007 at 9:37 AM, padgett said: Am assuming the the low beams stay on when you try to go to brights, if they go out, you have a different problem. 1) Either buy the service manual or download it from Reatta.net. 2) Look in section 8A-100 (in file 8A08 if downloaded) 3) No Reatta came with the twilight sentinel. The circuit is similar for both and goes through several relays. Breaker 21 provides power but if you are getting low beams the only one of interest is the hi-lo relay which is controlled by the BCM. 4) Are your fog lights working properly ? If not look to fuse 10 (parking lights). 5) If they are then you are left with the relay, the relay socket, the the wire to the BCM, the hot lead, the BCM , the HI beam socket, the HI beam filaments or the wiring from the relay to the HI beams. 6) To start, turn the headlights on and remove the relay - headlights should go out but parking lights stay on (if not, that was the wrong relay). 7) Jumper pin 1 (yellow wire) to pin 4 (light green). Did the HI beams come on ? 😎 Jumper pin 1 to pin 3 (tan). Did the LO beams come on ? 9) If both came on then the problem is in the primary circuit of the relay. (coil, BCM, wiring, socket, power) 10) If only the LO beams came on, then the problem is in the secondary wiring to the HI beams (relay socket, wiring to lights, light sockets, filaments. 11) if the primary circuit is the problem , check the relay socket for 12v on pin 5 (orange & hot all of the time) 12) If have 12v and the relay is good then the problem is in the socket, the wire to the BCM, the BCM connector, or the BCM. Last night I went to install an aftermarket headlight relay harness in my 1990 'vert. Installation went fine however I wished I would have tried all the lights before installation as I am blowing fuse #10 immediately and I have no running lights or high beam switching [although the indicator in the dash shows high beam when switched from high to low]. I disconnected the aftermarket headlight harness which returns the car to stock but still blow #10 fuses and still have no running lights or high/low beam. Fortunately I was at Kendalls [my mechanics friend] house and we swapped out the headlight switch with another known good one [completely stock no rebuild] and we keep blowing fuses. It does throw a b420c code and we didn't have time to do the diagnostic tree but I am leaning towards a BCM. Can a bad BCM cause a dead short situation by blowing the fuse as soon as the headlight or running light button is activated? Installing a new fuse and then pushing the fog light button does not blow a fuse. I was able to drive the car home because while fuse #10 is blown the headlights/brake lights still work but I don't have running lights so it was 4 way flashers all the way home. Link to comment Share on other sites More sharing options...
Ronnie Posted January 13, 2021 Share Posted January 13, 2021 Dave I don't know for sure what fuse #10 is on your '90 but I will give this a shot. I don't believe the BCM will cause a short that would blow a fuse although it might be possible. The BCM only controls the relays and isn't part of the circuit that powers the lights. I believe the short is in a circuit going through the contacts in the hi/low beam relay or some other relay. It may not be the relay it's self but start by replacing the relays that control the lights if you haven't done so and see if the fuse still blows. Then unplug all the relays and start installing them one at a time until the fuse blows. That might tell you where to start looking for the short. Just a shot in the dark... check the headlight bulb connectors carefully to make sure you didn't short out a wire in or around the connector when you were working with it to plug in the harness. As you know those wires are fragile and prone to breaking so one of them might have been damaged and caused a short to ground. The photo below shows what I found on my headlight connector. Link to comment Share on other sites More sharing options...
DAVES89 Posted January 13, 2021 Share Posted January 13, 2021 We had all the relays out and tried the switch and still blew the fuse. We will check the headlight connectors as you suggested and hope that is it. Link to comment Share on other sites More sharing options...
padgett Posted January 13, 2021 Share Posted January 13, 2021 (edited) Fuse 10 is the parking/running lights and hi/lo relay. In 90 there are early and late, not sure what difference is. Drat, cannot attach a .pdf. Should be able to pull relay and jumper to test circuits. I'd use a DVM orlightbulb to test for shorts first. Short in BCM is possible but unlikely, is a relay to ground so short should just turn hi beams on. Edited January 13, 2021 by padgett (see edit history) Link to comment Share on other sites More sharing options...
Ronnie Posted January 13, 2021 Share Posted January 13, 2021 When I look at the wiring diagram Padgett posted I don't see how fuse #10 could blow if both the fog light relay and the hi/lo beam relay are removed - unless, it is blowing as soon as you install it, before any lights are turned on. In that case there could be a short in the wiring between the #10 fuse and the relays. Link to comment Share on other sites More sharing options...
Ronnie Posted January 13, 2021 Share Posted January 13, 2021 I just looked at the '89 FSM and it shows that fuse #10 powers the headlight switch as well as the hi/lo headlight relays and several others. That opens the door to a lot of relays and circuits that could cause the short. I assume the '90 FSM is basically the same. Link to comment Share on other sites More sharing options...
DAVES89 Posted January 13, 2021 Share Posted January 13, 2021 That #10 fuse runs a lot of things. If the headlight switch is in the complete off position the fuse does not blow. If the Fog Light button is activated the fog lights comes on and the fuse does not blow. However the running lights do not come on. Then when either the running light or headlight button is activated the #10 fuse blows. However the headlight comes on but will not go to brights. I am leaning to the headlight plug. When I was adjusting the up stop I also wanted to swap in Silver Star headlights. I couldn't get the headlight plug to release with my fingers so I used a channel lock pliers to pull the plug off. I am thinking that the short is in the drivers side plug and is blowing the fuse even if it is disconnected from the bulb. Link to comment Share on other sites More sharing options...
padgett Posted January 13, 2021 Share Posted January 13, 2021 My post was from the '90 manual. Link to comment Share on other sites More sharing options...
padgett Posted January 13, 2021 Share Posted January 13, 2021 Think are looking in the rong place. Really need a copy of the FSM particularly for wiring. This is page 8A-11-9. Link to comment Share on other sites More sharing options...
Ronnie Posted January 14, 2021 Share Posted January 14, 2021 That looks like the same diagram that I was looking at for the '89 that I commented about earlier. Link to comment Share on other sites More sharing options...
padgett Posted January 14, 2021 Share Posted January 14, 2021 Maybe is time to contact GM again about posting our scanned manuals. Since not searchable should not conflict with Bishko or Helm. I have contacted Bishko before about a .pdf Reatta/Riviera manual but they have never replied. (They have all Allante manuals on CD). Link to comment Share on other sites More sharing options...
DAVES89 Posted January 14, 2021 Share Posted January 14, 2021 After another 6 hours of work, pulling all the relays, circuit breakers, and disconnecting modules, headlights, taillights, and tripping the #10 20 amp fuse about 30 plus times, we decided that we were going to try one more time. So we reconnected all the modules and reinstalled all the circuit breakers and relays except for the running light relay and tried one last time, and everything worked! So as we put back each of the following; the stereo, temperature control, headlight switch, IPC, glove box, under hood light, taillight, headlights, we would test making sure we were good. We got to the driver's seat [never took out the passenger] and then tested and all our problems came right back. Removed the seat rolled back the carpet and saw that the connections for the wires were corroded. That was the ground side. We did a couple of the worst [it was after 10:00 pm] tried it on last time, no luck. Finished putting the seat in and drove home with low beams, no running lights or tail lights but had brakes. We will do the connections as we get closer to spring. Snow is coming and I don't want salt on the car. I was surprised that the corrosion was so bad. I bought this car third hand from the guy who knew the dealer [the dealer was the original owner, bought it for his wife]. I just expected the car to always be an "inside" car especially as clean as it was/is. Link to comment Share on other sites More sharing options...
Ronnie Posted January 15, 2021 Share Posted January 15, 2021 Are you saying the short is in the splices under the seats? Link to comment Share on other sites More sharing options...
DAVES89 Posted January 15, 2021 Share Posted January 15, 2021 (edited) We have a "dead" short, the fuse blowing is immediate and as we had disconnected everything [see previous post] there really was no reason for anything to blow. But after we saw what was under the carpet on the drivers side we thought we would look at the passenger side. It has to be it, as we did get everything working [for about 20 minutes] and then it went back to blowing fuses. It is a good place to start at because no matter what, the connections need to be done. I am interested to see what the passenger side looks like. Edited January 15, 2021 by DAVES89 (see edit history) 2 Link to comment Share on other sites More sharing options...
padgett Posted January 15, 2021 Share Posted January 15, 2021 BTW, I usually check with a 12v bulb in place of the fuse. If it turns on you have a short but does not blow anything. Link to comment Share on other sites More sharing options...
DAVES89 Posted January 15, 2021 Share Posted January 15, 2021 (edited) 1 hour ago, padgett said: BTW, I usually check with a 12v bulb in place of the fuse. If it turns on you have a short but does not blow anything. Great idea. I'll give it a try. How did you make it? Edited January 15, 2021 by DAVES89 (see edit history) Link to comment Share on other sites More sharing options...
padgett Posted January 15, 2021 Share Posted January 15, 2021 12v bulb, socket, some wire. Link to comment Share on other sites More sharing options...
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