Aztec62 Posted June 19, 2017 Share Posted June 19, 2017 On 6/19/2017 at 10:02 AM, Ronnie said: If your IPC looks like the one in the photo below when you press the test button it proves there is nothing wrong with your IPC. That is the first thing that needs to be ruled out - even though it was working before. The reason I ask about the dimmer is this: If you have a bad twilight sensor (photocell that senses day and night and automatically dims the IPC) AND the dimmer slider is all the way to the left, the IPC could be so dim that you can't see anything on it. A bad photocell on the Reatta is a common problem. Again, this is something that needs to be ruled out before doing more troubleshooting. http://zombdrive.com/images/1991-buick-reatta-3.jpg[/img] Ronnie, as far as I know, pressing the "Test" button on the IPC is by no means a comprehensive test for the IPC. All it does is to show that it is connected to power, it lights fully up, no burned bulb or missing digits etc. delsol54, when you see this information: Link to comment Share on other sites More sharing options...
Ronnie Posted June 19, 2017 Share Posted June 19, 2017 Ronnie, as far as I know, pressing the "Test" button on the IPC is by no means a comprehensive test for the IPC. All it does is to show that it is connected to power, it lights fully up, no burned bulb or missing digits etc. delsol54, when you see this information: You can almost be certain your IPC is gone. I have exactly the same issue on my 90`Reatta. The problem does not show instantly when the ignition is turned on. The IPC display is frozen, and I am unable to enter diagnostics by pushing the climate control buttons. Only after a few minutes the error like in the above photo shows. Maybe the same on your Reatta, just wait... I do not think you have killed the IPC on your Reatta. I think it`s number was up, that is all. Go have it repaired or get a known good used IPC. A very common problem on all 90/91 Buick Reatta and Riviera. Fixing it is nothing DIY, even with an electronic background like I have. The informations needed are not available and the electronic componets wear special (GM?) designations which tell you nothing at all. I have opened up the defective unit I have and was unable to tell the function of any IC present on the IPC´s electronic boards. This is something for the specialists. Have fun Henning I agree that the test button isn't a comprehensive test of the IPC but it does tell you the IPC is capable of lighting up. I can also agree that it is time to replace or repair the IPC if it reads "ERROR" but if it is just blank I think it would be a little premature to replace the IPC until further testing is done. If the problem was as simple as a bad IPC the check engine light should start flashing (at least it does on my '88 model) when on-board diagnostics is accessed. He says that doesn't happen. That tells me there is more to this problem than a bad IPC. All this is puzzling to me and I think it is a problem that is going to require a '90 FSM in hand to resolve. There are several pages of flow charts that must be followed to narrow down the possibilities of what is going on. Link to comment Share on other sites More sharing options...
delsol54 Posted June 19, 2017 Topic Author Share Posted June 19, 2017 no i do not have a service manual Link to comment Share on other sites More sharing options...
Aztec62 Posted June 19, 2017 Share Posted June 19, 2017 delsol54, A service manual for the 1990 Buick Reatta/ Riviera is only available in printed form. For the 91 model you can get a pdf file but that won`t help you much. There are a lot of things (a little) different. I got my copy from Rockauto.com: http://www.rockauto.com/en/catalog/buick,1990,reatta,3.8l+231cid+v6,1019911,literature,repair+manual,10335 Available for about 100 bucks. Or buy directly from BISHKO: http://www.autobooksbishko.com/search.cgi?year=1990&make=Buick&category=Shop+Manual Have fun, Henning Link to comment Share on other sites More sharing options...
Ronnie Posted June 19, 2017 Share Posted June 19, 2017 You said the IPC worked before. Has it worked since you've owned the car? Link to comment Share on other sites More sharing options...
Ronnie Posted June 19, 2017 Share Posted June 19, 2017 delsol54, A service manual for the 1990 Buick Reatta/ Riviera is only available in printed form. For the 91 model you can get a pdf file but that won`t help you much. There are a lot of things (a little) different. I got my copy from Rockauto.com: http://www.rockauto.com/en/catalog/buick,1990,reatta,3.8l+231cid+v6,1019911,literature,repair+manual,10335 Available for about 100 bucks. Or buy directly from BISHKO: http://www.autobooksbishko.com/search.cgi?year=1990&make=Buick&category=Shop+Manual Have fun, Henning Another good place to find the manuals is the Reatta Store. If you order from there it helps support this website. Link to comment Share on other sites More sharing options...
DAVES89 Posted June 19, 2017 Share Posted June 19, 2017 About 3 months ago I came across that yard near West Bend with all the Rivs and Reattas. There was one Reatta that was in great condition [the '90 Red/Tan] and I got a lot of parts off including a rebuilt IPC. I took a chance and bought two ther IPC's from other cars that use the Reatta 1990 IPC took them home and tried them, they wouldn't even light up. In the past I have junk yard tested IPCs that would light up in test but not work when the car would start. I also junk yard tested IPCs that only the idiot lights worked when I pressed the test button. My opinion is that if all the fuses are good and the CPS works the IPC is bad. Henning is correct either send yours in for repairs or search out another working IPC. The IPC in the 90/91 Reatta is a known Achilles heal and one should always have an extra. If you like the car and plan on keeping it, buy some extra parts. There is a small parts shortage now that will only get worse. The last car that used our IPC was the 1993 Riviera and that car is now going to be 25 years old. There are no late model cars we can use parts from. The "C" motor and transmission we use has only a 3 year run. Parts for these things aren't as common as they used to be. And there were 100s of thousands of those made. Link to comment Share on other sites More sharing options...
Frogware Posted June 19, 2017 Share Posted June 19, 2017 Don, About the headlight switch - When I first got my Reatta I was going through everything in the interior making sure it was good mostly lights. Well I noticed that the illumination light on the headlight switch was burnt out or not working, so I decided to fix it one day....Ooops! Little did I know how complex that switch unit was and like you I ended up with parts flying everywhere. Well after fixing it so I thought I put it back in, but didn't try it because I had the battery disconnected since I was messing with the electrical so I had to wait a while. When I finally tried the switch well I had similar results as you are having. My IPC was dong weird stuff and a few other problems that I can't remember right now, I think I got the ERROR in the display. But I didn't know that is what was causing my problems because I was installing a new radio and fiddling with the electrical stuff at the same time so it took me a while to figure out that I had put the switch together wrong. I couldn't really test the lights until it was dark so that is why I didn't know that was the problem until it got dark and found that my lights were not working correctly. So I had to tear apart the switch again and figure out the correct way to put it together. A hint: when you press the Lights button, internally it will also press the Parking lights, and if I remember right those metal connecting bars go in a certain way to make contact to complete the circuit. I had to tear apart this thing 3 more times because it didn't work right, just so you know it was a PITA. I finally got it right and everything worked great. I hope this helps and maybe you already solved the problem and it wasn't the light switch but in any case if you checked everything else you might want to recheck the switch. -Scott Link to comment Share on other sites More sharing options...
Ronnie Posted June 20, 2017 Share Posted June 20, 2017 I really think you might be on to something Scott. That would explain why sliding the dimmer all the way to the right has no effect on the interior lights. Link to comment Share on other sites More sharing options...
DAVES89 Posted June 20, 2017 Share Posted June 20, 2017 I have an extra United Radio rebuilt IPC as well as rebuilt to NOS 1990 Reatta [only] headlight switches. If interested you can email me at; lemke1044@aol.com Link to comment Share on other sites More sharing options...
delsol54 Posted June 20, 2017 Topic Author Share Posted June 20, 2017 I dropped my car off to someone who has great knowledge of OBD1. I'll report back as soon as I have something Link to comment Share on other sites More sharing options...
Ronnie Posted June 20, 2017 Share Posted June 20, 2017 Thanks for letting us know. I look forward to hearing what they find. Link to comment Share on other sites More sharing options...
delsol54 Posted July 3, 2017 Topic Author Share Posted July 3, 2017 hello all, i got my car back and the problem was ECM. it effected all of the problems i had explained. everything that worked before now works again. i thought it was the ECM all the time because of the number of things that were effected all at the same time. not having the correct tools to scan the ECM required someone who did. Now the only issue i have and I'm sure its the result of changing the ECM is air blows to defrost only which indicates a vacuum leak at the air controller, which haven't been able to find yet. its got to be the problem because when i suck on the line in the engine bay, it doesn't hold vacuum, thus a vacuum leak up where the boys were last week. now i just got to find the controller up under the dash left of the glove box, Correct?????? is that the right location.????? Link to comment Share on other sites More sharing options...
DAVES89 Posted July 3, 2017 Share Posted July 3, 2017 It is located in the same general area as the ECM. Remove the kick panel on the passenger side and you will see 4 colored hoses and one black one going to a black box with a cardboard lid. I am betting a hose became dislodged. You can check and reconnect the hoses without removing the controller. The other thing that could have happened is that the rod became disloidged. To get at that you need to remove the glove box. The glove box is held in place by 8 torx screws. Once the screws are out you should be able to slid the glove box out far enough to see what is going on with the rod. However I would start with the vacuum hoses at the controller first. Link to comment Share on other sites More sharing options...
delsol54 Posted July 4, 2017 Topic Author Share Posted July 4, 2017 Found it and plug in the vacuum line and everything works as it should ty Link to comment Share on other sites More sharing options...
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