I purchased a 2002 Corvette Z06 recently and have a few issues I need to get sorted out. It was in a minor accident and I'm just now getting it back on the road after being in the body shop.

Both headlights do not pop up. I had to prop them up manually. The lights themselves work.
Both power windows do not work. I do hear a relay clicking in each door when I push the buttons on both doors.
The instrument cluster lights do not light up with the lights on. They do light up when I turn the car off.

Any ideas? All related fuses seem good, but I did not check every fuse in the boxes. Does it sound like a bad ground or something? I find it hard to believe that so many things could be wrong at once...especially both sides.

If the ground sounds likely, where do I check? I've read that grounding can be problematic on C5s, but the link to the ground locations was broken.

Thanks!

 

Bill Curlee, where are you? BTW, Bill is the Ben Franklin and Nikola Tesla of Corvettes. Trust me, he will be able to assist as he has many of the other corvette owners with electrical issues.
Mike C

 

Well, the headlamps turning on but not popping up issue: the headlamp switch sends a signal to the bcm or the headlamp control module directly(I don't remember which this moment) which in turn, the headlamp control module raises or lowers the lamps. If you have the twighlight sentinel on the car, disable it in the DIC and try again, let us know what happens. While you are doing this, open the passenger side headlamp and look behind it on the car's frame at the headlamp control module mounted there. There are exactly two connectors on it that must be plugged in all the way. Now, before doing that, disconnect the connector to that same headlamp so it doesn't close on your arm!

The instrument light issue is probably a bad headlamp switch. Common failure item. You are take it apart and repair the contacts or just replace it.

The windows not going down: check the window motor fuses. If they are good, then try rapping on the top edge of the window with your hand while pushing the down button. If this doesn't get them going, you'll need to pull the door sides off(internal) access the window motors, disconnect the connector to it and verify if power is getting there or not.
As stated, Bill is the expert and can advise you better. Doing these simple things I've suggested here, your answers will help him and us to help you.

 

Thanks for the advice!

I finally got a chance to look at it today. The body shop painted the frame rails completely and bolted the front 4 chassis grounds back directly on top of the paint. So, I thought I had everything solved with such an obvious problem, but nothing changed after removing the paint and re-installing.

So, I plan to tackle it again tomorrow. The instrument stalk definitely seems like it's the culprit for the headlight and instrument panel issues. I noticed the taillights also don't illuminate with the lights on, so that's another common indicator of a stalk issue.

The window fuses are fine and tapping the top edge does not change anything. I tried banging on the door panel and adjusting the door jam wiring to no avail. It seems strange that they are both stuck. I do hear the relay clicking and I notice that the headlights dim slightly when the button is pressed as if it's drawing significant current, so I'm wondering if the motors are seized. I guess the door panels will be coming off.

One problem I didn't mention was the ABS and TCS lights on the dashboard. I get the following warning codes:

10 P1571
28 No COMM
58 U1040 HC

When I first accessed the DIC, I had 10-15 codes, but the three above are the only ones remaining after clearing all and driving it. From what I've read, this is an EBCM problem. I'll check the harness and fuses tomorrow for it.

One other strange problem is a clicking noise with the key in the ON position and the engine OFF. I'm not sure if this is the fuel pump or something else. It did nearly drain my battery after having it in the ON position to check the DIC codes.

Thanks again.

 

I took apart the column stalk assembly and bent the pins as instructed. This did not correct the light problems.

One thing I noticed was that the battery voltage is low with the engine off. It reads around 11.9 volts after shutting the car off. After working on the column stalk, it nearly wouldn't start. The only drain would have been turning the headlights on and off (short time period). I'm starting to think the battery is bad despite it being new. The car always cranks over slow...even after only a few minutes of being off.

I have gone a week without starting the car and it still started similar to how it does after an hour of not starting, so I don't think there's a huge drain on it or the battery would be gone by then.

Could this cause any of the issues? I have 14+ volts while running, so it would seem like everything would be OK while the car is on.

I'm also getting a B2592 code again.

Thanks again.

 

The C-5 requires a minimum of 12.5vdc static across the battery with the ignition off. How old is your battery? If its beyond 3 years then you might want to consider replacing it but at least, have it loaded tested.
The code you saw
B2592 Column Lock/Unlock Drive (B)

Not sure there, but start with the battery.

 

I swapped the battery, but it did not fix the problems. It does start eagerly now. The old battery did test bad, so it was needed anyways.

I took a look at the BCM and have some questions. All BCM fuses have 12+ volts going to them. In the manual, I see the following:

9 - Body Control Module
13 - Body Control Module - Ignition 1
22 - Body Control Module - Ignition 3 (Fuse missing?)
23 - Body Control Module - Ignition 2
25 - Body Control Module - Ignition 1

These all tested fine aside from #22 which is missing. Is this for an optional feature?

I took some pics of some cut wires I found near the BCM. I found the box pictured that tapped into these lines. I'm not sure if this is some kind of aftermarket device or something factory. It has two ethernet-type ports on it.

What is the purpose of the pictured harness that has wires cut on it?





I also see these two plugs. Just checking to make sure they're not supposed to be plugged into anything.

 

The black device is the power junction for a ValentineOne Radar Detector. The two gray connectors are the serial data buss interface connections.

 

.....and the taped wires are the accessory wires.

 

I guess I can mark that off the list.

A glimmer of hope just now when the driver power window started working. I pulled the harnesses out of the door and kept pressing the button. It moved slowly for a few inches and then started working normally. I'll check the connections closer, but I think it was a seized motor that coincidentally freed up while messing with the wires since I kept pressing the button. The other side still has the same symptoms (relay clicking and significant current draw that dims the lights), so I'll probably have to pull that door panel off and look at the motor. I'm hoping that they were just both seized from months of no use.

The connection to the EBCM unit looks fine, so I'm debating over sending it off to be rebuilt since the rebuild prices on Ebay are very reasonable with good feedback.

 

P1571 indicates the PCM is not seeing a good signal on the requested torque line. That could be a problem at the PCM, at the EBCM, a wiring issue between the two, a bad ground at G108 or a bad voltage connection to the EBCM. Since you seem to have some voltage/ground issues I wouldn't recommend sending out the EBCM until the other issues are resolved. I would also verify the place can actually repair the problem you are having.

Have you checked the wiring in the door accordians? Sometimes the insulation wears through with resultant shorts and you get some wierd voltage effects.

Bill