1994 Coup, 6-spd manual, electrical problems?

Description of problems.

Issue #1: During a hard acceleration, the red brake light on my dash board will randomly light up temporarily for a few seconds and then go off. This does not happen often; actually, very rarely. However, yesterday, the brake light did not go off for quite a while and then two amber warning lights came on the main display. One was for "ASR" and the other was for "Service ABS". The car was not on gravel or any surface that warranted the ASR light. Anyway, the lights remained on (I do not remember if the red brake light remained on or not). So, after driving for a few miles, I pulled over, turned the car off, .....then back on,.... and the lights did not come back on. FYI.....I have replaced both front and back brakes within the last year or two and have not driven the car enough to warrant new brakes.....

In the past I have not paid much attention to the red brake light because it always occurred during an acceleration and it was not more than a flash. If it occurred while applying the brakes, I would assume something is wrong. So, I just never put a lot of thought into it. Probably, the wrong way to think....Anyway, now that the two amber lights came on, I have no idea what to think or where to start.

Thoughts?

Issue #2: Ever since I got the car,....maybe five years ago.....whenever I close my door, the locks on both doors will many times (more times then not) always move to 'unlocked' position....or toggle back and forth as if it is getting an electrical signal. Sometimes, when I turn the car off and open my door, the inside lights do not respond unless I jiggle the push button on the door, then the interior lights respond.

Issue #3: If I turn off the car, leave my lights on and open my door with the lights still on, I do not get a warning buzzer.

I assume Issue #2, and #3 may have the same source of problem.

Thoughts?

thanks

kce

 

Issue #1: Check your brake fluid level. If it is not up to the full mark. It needs to be, these cars seem to be susceptible to those lights even if it appears to be full enough. Fill it to the max. line.

Issue #2 and 3. Could be related sounds like your door switch might be intermittently working. They could have a loose connection or just a dirty one. These cars are not young. You did not say if your using or have a PKE on your 94?

Do you ever get a buzzer? There is a chime module if memory serves me correctly.
With C4 electrical issues you really need to get a FSM and learn how the system works and do some testing. Anything else is speculation and guessing regardless of what anyone else might say to contrary. We can suggest likely causes but until you get into the car and do some testing it is all hearsay.

 

thanks for ideas.

checking brake fluid is easy and if the sensor is that sensitive, it does make sense that if the fluid is not 'Full' and with a hard acceleration that the fluid may move enough to activate it.

Buzzer vs chime.....I think it is a buzzer; however, since it rarely works, I do not know.

I am suspect of a loose connection on the door based on the fact that when I push the button on the door "in and out", I get different responses on the interior lights. Plus, the clicking of the locks when I close the door....

I do have a FSM......not sure I am ready to tackle schematics, but have done it in the past..... and can look for a module for that part of the car....

What is PKE?

 

Since you have the FSM - 5-2 in the FSM should cover the BRAKE/ASR/ABS light sequences and how it's maybe related to some diagnostics. Fluid level is certainly a "first check".

PKE is the remote entry for the C4, Passive Keyless Entry requires a read of the owners manual or the FSM to understand well. You likely have both.

Your '94 also has DAB (8A-15) so your experiences with "KEY IN IGN" and "KEY IN HAND" are maybe best explained in the owners also. The fact that you can maybe alter the responses when fiddling with the AJAR switches hints a potential issue there.

The 8A section isn't very intimidating so long as you do just a single system at a time. Diagnostic hints are generally on the page or pages following the wiring schematic.

 

Happens to me from time to time. Got to be 100% to the mark.

My PKE and door locks appear haunted as well. If I pull the key out or if partial in cylinder, the locks will swish around. The PKE controls the door locks and it's got a mind of its own but works 100% under normal operation.


As said, do the chimes work at all. There are 3 ring combinations that you can have.

The chime box sits on top of the PKE module under the dash pad. The chimes are controlled by the CCM module. It's a simple box with only ground, power, and 2 inputs that get grounded by the CCM (in different configurations) to make the 3 chime sounds. It can be trouble shot from outside the car easily on the bench. I have repaired 2 of these and both times found bad solder connections. Although the solder looked good, it was the tower or chime heavy connections that were bad on the sides of the board that needed to be reflowed. It's not like a regular speaker, it's a bit of a unique setup. The electronics or the driver amplifier was never bad.

Removing the dash pad will take care due to old plastic, lots of hours and effort. For me it was a weekend project and worth it.

 

Grab the door switch plungers and pull them out then close the door to ajust. Put your parking brake on and off a few times then try cleaning the carpet fibers and french fries or pennys out.

 

Thanks for all the input.

Somewhat disappointing that the dash pad would need to be removed in order to get to the chime box......I may wait until it warms up to help prevent breaking cold plastic pieces.....and then, only after I have performed some diagnostics and eliminate all other options.....I also have some lights out on the front console (for my defrost and fan setting buttons); so, I already need to pull the front of the console to either clean up the contacts or replaces some bulbs....

I did not know the door switch plungers could be 'pulled out'.....I assumed the door panel would need to be removed in order to get to the wires, etc.

 

I am talking about the the door plunger to ajust. On mine to pull the switch loosen bothe screws then take one out then turn the switch and put the screw back so you do not drop parts in the door.

 

You don't have to get to the wires to pull the plunger out. Just grab the plunger with a pair of needle nosed pliers and gently pull. If that doesn't help, then you will probably need to replace the switch. If you follow antfarmer's procedure, you can change the switch without removing the panel. On the other hand, if, in the process you hear "clink, tinkle, trinkle" from within the door, then the panel will have to come off.

Good luck.

 

This is the old style door ajar switch, but the principle is the same. The nut plate is actually captured by the harness but it can slide down inside the door. I had to fish mine out with a magnetic pickup tool. The trick is to loosen both screws and then move the switch to the side and screw one screw back in to hold the nut plate.

This shows the plunger center part pulled out:



This is the new style switch with the connector built in to the switch. It uses the same nut plate to mount it: