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1989 Reatta with two issues (and a bunch of smaller ones..): ICP flickers and no DRL


ClaretRed89

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Hi,

 

I'm from Switzerland. I recently bought a 1989 Reatta. Since the car was never officially imported to Switzerland it must be super rare over here. I love it. It had one big issue, the headlight switch had molten. I replaced it and had an electrician set up two relays with fuses for both low and high beam headlights.

The new light switch works perfectly including the dimmer, veryfied it in service mode, headlights work great too. Yet, each time I switch the headlights on the IPC starts flickering and going crazy. The BCM throws a B336 code, the instruments stop working etc. 
I suspect a wiring issue. The data line and the backlightning line are neighbors on the connector. What do you think? A contact issue or a broken IPC? Everything else including the touch screen works fine.

The second issue concerns DRL. Daytime lightning is mandatory in Switzerland. I tried the BS06 override and changed it to 48 but no DRL. What am I missing? Is there a relay I need to check and if yes, where is it? I haven't found anything in the service manual.

 

Thanks a lot for any advice


Pip

Edited by ClaretRed89
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Welcome to the Forum!! 

 

I will have to think about your IPC issue and look at the FSM to see what I can come up with that might be causing the problem. Maybe someone will chime in with some ideas. It would be helpful to know exactly how the new low and high beam relays were installed.

 

Will driving with the fog lights on all the time satisfy your need for DRLs? Many people, including me, keep the fog lights on all the time and it doesn't hurt anything with doing so.

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Wow! You are quick! Thanks for the welcome!

Unfortunately the laws are very restrictive over here and fog lights are not allowed unless there's thick fog. So atm I can choose between getting fined for not having lights on or for having the wrong ones on. Cops tend to cut classic car owners some slack though so I might get away with no lights for the time being. I can always resort to some ugly led driving lights but if there's a chance I'd rather get the original solution working. 

But the flickering is the more problematic issue anyway. Lights off, everything is fine, lights on its really bad and I am a bit worried I could actually damage the IPC if I don't solve the issue. 

 

The additional relays sit between the light switch and the headlights. They got their own fuses and are directly connected to the battery. Basically, the light switch now switches the relay instead of the light itself. They are not the cause of the issue though. I removed the damaged switch and while I was waiting for the replacement  I once tested the fog lights and the dash would flicker even without the headlight switch and w/o the headlights being on. In fact it starts flickering already with the parking lights. That's why I think its either a damaged/shorted wire or a damaged IPC.

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I would have the alternator checked, or better still, swap it  out for one that you know is good. It's possible the rectifier in the alternator is bad and when it gets a load on it instead of putting out pure 12 volts DC it could be putting out AC voltage. The only time I have seem my IPC flicker like you describe is when I had a battery charger on a dead battery and turned the key on.

 

Back to the DRLs. If you turn the fog lights on all the exterior lights will come on anytime the key is turned to run. If you remove the bulbs from the fog lights you would have DRLs unless the light is required to come from the headlight bulbs. Surely that isn't required in your country? If so you would have to drive around all the time with headlight doors open.

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What lights are to be illuminated as DRL? As far as I know, the present system on the Reatta was because of a Canadien requirement for DRL? In the U.S. DRL has been trialed, then mandated, then no longer required after 2018, but the one common item is only forward facing lights are used for DRL, no tail or side marker lights. Is that the Swiss requirement?

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I maybe can add a couple of things. First off the Fog Lights are not really Fog Lights as they have no illumination strength. Maybe if you installed LEDs bulbs one might then call them a Fog Light. I would run the Fog Light switch on to activate the running lights and let the authorities tell you different.

Regarding the headlight switch. You stated that the switch melted. If that is the case your connecting plug to the switch might have a bare area where the power is jumping into another circuit. I have had problems in the past with melted switches and bad connector plugs. All kinds of illumination things can happen as almost everything in the dash runs through the Headlight Switch and then to a lessor extent the fog light switch.

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@DAVES89 I have replaced the plug into the light switch as it was in a pretty bad shape too. But yes, I too think it's a bad connection somewhere. I need to check the connectors that go into the IPC I guess.
@Ronnie I suspect the battery is weak, I need to check it. I would never have looked into the alternator. But why does everything apart from the IPC work well when the lights are on? Wouldn't there be more issues if the alternator was bad? And when the lights are off everything including the IPC works perfectly fine. The flickering starts only with the lights on (even if it's only the parking lights). That's why I thought the problem should be located around or at the IPC. When it switches on its background lightning is when the flickering starts.

 

I guess I could use the fog lights as DRL but right now I think I will stick to the economical approach: the fine for not having lights on is cheaper than the one for having the wrong lights on, hahaha

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1 hour ago, ClaretRed89 said:

... why does everything apart from the IPC work well when the lights are on? Wouldn't there be more issues if the alternator was bad? And when the lights are off everything including the IPC works perfectly fine.

You may be right about the lights causing the problem. The only way t know for sure is doing some hands on testing to try and isolate the problem. I was just throwing the alternator out as the first thing I would check. An alternator putting out AC voltage can do lots of crazy things to a cars electrical system.

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I have no IPC illumination and will update when fixed. This pic is from my 1988 Service Manual. I found on my car that Cavity RTC is actually in RTD, which is a Dark Green Ground but I added the ground to RTC with no change. Just an FYI that the Service Manual seems wrong for at least that pin (cavity). 

image.jpg

Edited by Howdy2k2000
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1 hour ago, Howdy2k2000 said:

I have no IPC illumination and will update when fixed. This pic is from my 1988 Service Manual.

Welcome to the forum Howdy!

Give us the page number you are looking at in the Service Manual and I will look it up .

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Welcome! Wow, Switzerland! Even here in the States, the Reatta is becoming more rare by the day. I can't imagine there's more than a couple in your country IF THAT. 

 

I agree with those above on checking the alternator. Can you or your mechanic test for AC voltage at the battery while under a heavy load? Even a tiny ripple of AC voltage can cause havoc on digital displays.

 

You also mentioned that your battery may be weak. Keep in mind: a car NEEDS a strong battery not just to start, but to provide a buffer between the alternator and the vehicles electrical system. For example, the Reatta comes with a 105A alternator. However, that 105A is only produced at cruise RPM's. At idle, it's output could be as little as half depending on age and condition. 50A is EASILY spoken for by the full complement of exterior lights on a Reatta. Anything more than that, and you're begging for issues.

 

Replace the battery, test for AC voltage, and report back.

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Hmm.. the flickering happens even when the engine's off, the instrument panel flickers when I put the car in ignition and turn parking lights on. Thanks @Howdy2k2000 for the picture: if you look at the c2 connector, the serial data line and instrument panel dimming lines are neighbors on that connector. That's why I still think it's a short or a bad connection. The flickering starts and then the computer throws a "connection problem detected" message on the CRT (and in I get the B336H code in service mode). Anyway, I have an appointment with my mechanic. We will disassemble the dash and report back.

 

Concerning the daytime running lights: the option1 override code (BS06/BD90) seems to work. Before, with the standard US code, the car would revert to imperial each time I disconnected the battery. With the CAN/export code the car now starts with metric displays as soon as I reconnect the battery. I guess it knows it's an export car now. But no lights. I guess the previous owner must have tampered with them. I don't hear relays clicking either when I set the override code. I guess we will look at the internal relay box too to see if some relays are missing. Too bad DRL is undocumented in the service manual.

 

Thanks you all for the help!!

 

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Hey all, I got rid of the flickering, the problem persists though. 


Today was the day of Deconstruction. 😄
First of all (and unrelated to the flickering), I noticed that I have no background lightning on the switches and gearbox lever. That's when I remembered that I had a photocell code b119 in service mode. When I looked for the photocell I noticed someone hat crammed a 20amp fuse in the spot. There is no photo cell in my Buick. 
We then removed the ICP and noticed that a tab was broken and a plactic piece of one of the connectors was missing. Also, two pins in the back were bent (one on each connector). Somebody must have tampered with it before. So we straightened the pins and tested, no improvement. In the meantime I had bought another IPC from eBay, so we tested that one, still no improvement.
We then checked the plugs on the BCM. Everything fine on that side.

That was confusing. It's not the IPC, it's not the Photocell. The IPC must get weird signals, that's the only remaining options. So we tested a radical idea. We cut the 2A12 wire on the BCM plug (see red markings on the attached image). The 2A12 wire is a grey wire that controls incandescent dimming on the ICP. Cut the wire and attached a plug (so I can reconnect later). And -lo and behold- the flickering is gone and the cluster is dimmable (even w/o the photocell). 

 

So, workaround found. But what about the problem? Do I have a faulty BCM, because it sure feels like it?

 

Thanks


Pip

 

Edit: Clarification: only the fluorescent bit of the cluster and the CRT dim. Not the bulbs.

 

DSC_0436.JPG

Edited by ClaretRed89
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Btw. I was very impressed with how the dash was designed. The plastic elements are brittle after 30+ years of course, but the layout is really great. And it was very easy to work on and to disassemble. Impressive indeed.

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Ok, I found a photocell. Not only does it work, it also cured the B119 error. BD44 shows values between 10 and 90. 

 

...but still no background illumination. I'm starting to run out of ideas. The inverters?? Power supply module?? BCM?? Any suggestions?

 

HAHA! My bad. Forgot to reconnect that 2A12-wire. Without that there is no power to the luminescent foil and the inverters. Gotta try that next.

Edited by ClaretRed89
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