1989 c4 indicator lights help!!!

Kmatts · 08-29-2001, 09:24 AM

I have a '89 c4. the indicator lights "!", brake light and all wheel drive lights keep coming on randomly. sometimes the don't come on at all other times the come on after driving the car for 30 minutes. I have checked all the fuses and the are in good shape. I've heard that it could be the longitudinal sensor. Any Help is greatly appreiciated.

Britwrench · 08-29-2001, 03:54 PM

There is a good chance that the ignition wires, spark plug connectors or the distributor cap and rotor arm require replacing. With the engine running, disconnect the plug to the amplifier (bolted on the coil) try each one and note the difference in the engine running. If it runs rough on one set of plugs there is your problem. It's entirely possible the distributor drive belt has broken too!!

Eric Coffey · 08-29-2001, 04:32 PM

Sounds farmiliar! Check the below post for a possible solution.

www.pelicanparts.com/ultimate/Forum3/HTML/012165.html

-Eric

Kmatts · 08-30-2001, 04:44 AM

I also forgot to mention that after letting the '89 C4 sit for a week or two the battery will sometimes discharge. It doesn't always do this, just occasionaly.
Also, the indicator lights do not flicker once the come on, they stay on. So I don't think it is an issue with the voltage regulator. But I'm not really sure.
I hope this additional info helps with the diagnosis.

Kmatts · 08-30-2001, 12:27 PM

If anyone else has any ideas at all that may help me out please post it. I really appreicate all the help. thanks.

Kmatts · 08-31-2001, 04:29 AM

Thanks for the advice, but did you see my addtional post? The engine runs extremely smooth though, that's what I can't figure out. If it were the wires or cap, wouldn't I have a rough running engine?

Quote:

Originally posted by Britwrench:
There is a good chance that the ignition wires, spark plug connectors or the distributor cap and rotor arm require replacing. With the engine running, disconnect the plug to the amplifier (bolted on the coil) try each one and note the difference in the engine running. If it runs rough on one set of plugs there is your problem. It's entirely possible the distributor drive belt has broken too!!

Britwrench · 08-31-2001, 06:43 AM

Even though your engine runs smoothly you still may have an ignition fault. Whenever a customer complains of intermittent warning light problems, the first thing I do is carry out that check, which takes a couple of minutes. After that you can start looking at the charging system, grounds etc...

I have had 964s with broken dist belts that
the owner thought ran fine..

Britwrench · 08-31-2001, 06:46 AM

Oh yes.. the other thing a preventative maintenance item. Check the abs and brake boost pump relays, if the date is before, say 1992, REPLACE them. the boost pump relay can (will) stick and burn out the boost pump and wiring ($2000.00 to repair).
Also replace the DME relay of more than five years old.

Kmatts · 08-31-2001, 06:58 AM

Brit,
I'm not the best do it yourself guy. I also have a 78 SC that I'm much more comfortable with. Can you give me a little more info on how to check for this. I know there are two dist. caps and obvioulsy two sets of wires. Other than that I'm a little lost. I'm sure i can identify everything (often times with the use of a book) but I'm a bit fuzzy on how to approach it.OTE]Originally posted by Britwrench:
Oh yes.. the other thing a preventative maintenance item. Check the abs and brake boost pump relays, if the date is before, say 1992, REPLACE them. the boost pump relay can (will) stick and burn out the boost pump and wiring ($2000.00 to repair).
Also replace the DME relay of more than five years old.[/QUOTE]

Britwrench · 08-31-2001, 09:22 AM

Ok, let's see what we can do..

Look inside the engine compartment on the left hand side and you will see the two ignition coils. Bolted onto the coils are two
black boxes (of course!) with connector plugs on them. With the engine running pull one of the plugs off and note the engine sound, is it rough, does the engine misfire,
or pop. refit the plug and do the same with the other one. compare the idle performance, if it not similar you have a problem.
Trace the coil lead to the distributor cap and that will tell you which bank has a problem, if there is one.

The fuse board cover shows the positions of all of the relays.

Kmatts · 08-31-2001, 09:52 AM

Brit,
o.k. I'll give it a try this weekend. Hopefully I'll have the chance to reply to you sometime sat. or sunday. Thanks for your help.
Kyle.

Bill Wagner · 08-31-2001, 11:19 PM

Kmatts:

The brake lights and AWD lights are what trigger the "!" light. On the C4, the AWD system is closely linked with the ABS system.

My advice would be to take it to a shop with a Bosch Hammer, which is the electronic diagnostic tool used to read failure codes from your electronically controlled engine and transmission (964s use a CPU controlled power distribution system, and they all use brake fluid to maintain fluid pressure). The C4 is also suscpetible (VERY susceptible) to voltage fluctuations.

My advice:

1. Make sure your brake fluid is filled up properly.

2. Brake fluid on the C4s is supposed to be changed every 2 years, REGARDLESS of the miles on the car. If it hasn't been changed, get it done.

3. Get someone to read your fault codes with a Bosch hammer.

This problem could range from simple (bad battery, low/old brake fluid) to serious (hydraulic pump failure, diff lock failure, etc.).

Hope this helps,

Bill Wagner

Britwrench · 08-31-2001, 11:24 PM

Bill is right, depending on what lights are coming on even something as simple as low brake fluid will cause the lights to come on.

Changing the brake fluid inludes the clutch,
the 4wd actuators and and boost system.
It's easier to change the acutator fluid with the Bosch hammer to run the pump.

Kmatts · 09-04-2001, 04:50 AM

Thanks for the advice, I will double check the break fluid level and make an apt. to have the computer system checked w/ a Bosche Hammer.
Thanks again.
Kyle.