I have a stock '99 z28 that started having some crazy electronic issues. I'm not sure where this belongs since the problems with the car are all over the place, but if it needs to be moved somewhere else, please feel free. I put it here since it seems like an ignition problem to me.

Two nights ago I took the car to grab dinner and quickly noticed that my dash lights and environmental controls lights were not working. Upon further investigation i noticed that my tail lights and fog lamps were not working either, but my headlights and brake lights were. I checked the dimmer switch and tried manually turning on the headlights instead of letting the light sensor turn them on. This made no difference. The dimmer switch will turn on the interior lights if turned all the way up as it should.

Yesterday I had all of the same problems when I took the car to work, except now the speedo, tach, odometer cluster, radio, and water temp gauge are dead. The fuel gauge, volt meter, and oil pressure still (seem) to work. Some lights come on in the dash, like no seatbelt, but the ASR off light does not turn on (i'm not sure if the ASR switch is even working or not), brake light, and various other things do not come on.

After searching today I read some stuff about fusable links, grounds, and fuses/fuse boxes. I checked my fusable links today and they all seem to be in good condition with no wire insulation coming off and the contacts look good. I've checked all the fuses under the hood and in the car that have anything to do with anything that is not working and they are all fine.

After messing with the car today, it now will not crank but honks the horn once every time i try to crank it. The red light next to the steering column is flashing, so i'm guessing the VATS system has been tripped.

I am at a total loss here, i've been searching ls1tech and google for about two hours now with no results. Everything I do seems to make it worse! Please give me some idea what to try.

Thanks in advance!

Chris

Edit: changed the title in case anyone searches for similar problem.

 

Wow, Chris...and I thought that I had gremlins!
Maybe if you hotwire the headlights & rear lights to the starter, it will be ok. lol!
Is it possible that water found it's way into the wiring?
If not, one thing that I do first when there is a mystery like this is to move all of the wire bundles that you can reach. Disconnect the battery, then gently lift the harness in places where it might come in contact with the frame. This might also serve to separate wires within the bundles that may be grounded/shorted.
Good luck.

 

After re-reading your post...do the items which don't work ie speedo, tach, etc operate from a common fuse? Do the other items which don't operate, also operate from another common fuse?
Some of the stuff, like the courtesy lights, are associated with the Body Control Module.

 

are all the grounds good. its kinds wierd that you lost some on the pcm side and some bcm and some that dont go on ether. are you popping any codes

 

With the battery connected, move the wires & junction boxes by hand, and observe whether lights change/dash works.

 

I checked a four of the grounds today, but i know there are some more i need to get to. I checked the two by each side headlights, the one by the fusable links/battery and the one by the two fuse blocks under the hood. I didn't check any interior grounds.

I'm trying to figure out what the things that work and the things that don't work have in common. I started with the PCM/BCM, but like you said earlier... some are from each or neither, so i ruled that out.

I really don't see moisture being a problem since there has been almost no humidity or precipitation here in the last two weeks or so. I washed my car about 4 days ago, but i find it unlikely that it would take 2 days for water to cause a short... though possible i suppose.

Thanks for the ideas guys, keep the coming. At this point I still don't even have a clue what's going on. Tomorrow i'm checking the start fusable link and i'm going to try to find more grounds. I'm going to write down all the things that are not working and try to find the common between them.

The car isn't showing any codes, but the light might not be working. I don't have a code reader and I obviously can't drive it to Autozone. I guess this might be a good time to invest in a code reader...

Thanks again,
Chris

 

Is the car parked in a garage?
On the chance that water has found it's way in, I might leave the car in the sun with windows down (if they can be operated), or doors left open & hood up. I know this is a grasp, but the problems sound varied, kinda like water might have traveled in. This will allow moisture, if there is any, to evaporate.

 

gMag: you were semi-right (I think). I jacked up the car to check those grounds and found a puddle of power steering fluid on the ground. Apparently my PS pump has been spraying my alternator with PS fluid. The alternator, ground, and wire bundle are all soaked in PS fluid. I just went and got a PS pump and alternator and some electrical contact cleaner. I'm going to replace the pump and alternator and clean those wires up and see if that might be my problem.

Does that sound like it could be it? Anything else I should do while i'm in there?

Thanks guys, i'll let you know how it turns out!

Chris

 

That would be very nice, if fixing a problem helps fix another problem.
I had the same happen to me, except that I have no wire bundles near the power steer reservior. The alt did get soaked, though.
I thought that the $80+ dollar power steering pump @ Advance would be a better bet than the $38 AutoZone, but the Advance model leaked as well, and I ended up with the $38 version.

 

I got the PS pump and the Alternator put in. We found a short in the headlight switch that fixed the dash lights, tail lights, blinkers, fog lamps, etc. We found another short in the ignition wire that got the car running again. I am still down a radio, speedo, tach, and water temp gauge. I'm guessing there are shorts somewhere in the line to those things.

Does this seem plausible?

PS fluid messes with the alternator causing a surge that shorts all this stuff out.

I can find shorts and fix them all day long, but i'm worried these same things are just going to short out again at some point. I need to fix whatever is causing these shorts. Would a messed up alternator be able to cause this many shorts?

Chris

 

You mentioned that a wire bundle may have gotten wet from power steer fluid. Did you find wet wires, as well?

 

Yes, there was power steering fluid all over the place. I cleaned the wires and harnesses real good with electronic spray cleaner and let it dry good before I hooked the battery back up.

Looking at wiring diagrams and what not keeps leading us back to the PCM. We are trying to figure out a way to test to see if the PCM is bad or not.

Chris

 

If the ECM is bad, there's nothing that can be done.
Is there anything to lose by turning the key to see if all is well?
After my pump leaked, I placed an arched metal 'hood' about an inch above the alternator so this can't happen again.

 

The car runs. It runs like it should. I just have no instruments. The only things that work on the instrument panel is the oil pressure, seat belt light, and possibly the volt meter (i'm not sure if it's actually working or just spitting out values). The odometer box does not even come on, it's totally dead. The instrument panel lights now work as well as the environmental control lights.

Also doesn't work:

-- Hatch release (button and FOB)

-- Radio (the BCM appears to be good. I see no cracks/scorches/etc on the board. I see 12Vs to the "ignition" wire and about 2-3Vs to the "constant power" wire. I swapped a known working radio to see if the radio was fried and the known working radio did not work.)

-- Power mirrors

I've been running around this thing with the wiring diagrams and a multimeter for the past two days. I have ripped the instrument cluster, BCM, PCM, radio, and fuse box out of it. I am at a total loss at this point. I'm pretty sure I can fix the hatch release and power mirrors pretty easily, I just haven't messed with it. I'm much more concerned about my instruments for obvious reasons.

I pretty much have no ideas at this point.

Chris

 

Ok, I feel like an idiot. I had my dad helping me with all of this. Naturally the first thing we checked were all the fuses even closely related to these problems. I checked the fuses under the hood and my dad checked the interior fuse box. He found the burnt fuse for the lights, which lead to us replacing the headlight/dimmer switch and solving that problem. He told me all of the other fuses were good. Today as i was searching for answers on ls1tech i came across a thread were a guy talks about having the almost exact same problem as me. His solution ended up being a bad ground on the instrument panel harness, so he just made a ground straight from the harness to the ground stud under the driver side kicker panel. Another guy in the thread said his problem was simply a blown power accessory fuse. I wrote down the schematics for the instrument panel harness and decided I would check those two things next. I *almost* didn't check the fuse because my dad had already done that. I thought i would double check it to make sure though... and guess what. It was a dead fuse. So i'm sitting in the car with the instrument panel, BCM, radio, most of the dash, and various other pieces of my interior scattered all over the garage thinking that if I had only double checked my dad I would have saved us both about 5 hours of work. The poor guy felt like such an idiot and I felt like an idiot for not double checking the simplest and most obvious likely culprit.

So from start to finished I replaced:

Alternator
power steering pump
headlight/dimmer switch and fuse
power accessory fuse

Obviously something caused the short in the switch and the two blown fuses. The power steering pump was toasted, and replacing the alternator might not have been necessary, but it makes me feel a lot better.

Hopefully me telling everyone that i'm an idiot will help some one else not be an idiot in the future

Here is the thread i was talking about in case some one finds this in search:

https://ls1tech.com/forums/stereo-el...king-help.html

Chris

 

sorry to thread jack but need help alarm messed up on my 2000 z28 the alarm keeps going off when you walk more then 10 feet away from it it goes off and the horn honks twice walk farther away i goes off and wont stop i put new a battery in the key change but didnt help any idea whats causing it or how to fix it without just taking the alarm system out .......thanks

 

Two suggestions... first do a search in the forum for similar problems and second, if you don't find anything, start a new thread rather than an off-topic post in an existing thread.

The alarm problem is probably caused by moisture in the shock sensor - a very common problem. The shock sensor is on the right rear wheel housing in front of the spare tire. Unplug it and the problem should go away. Then you can decide whether it's worth replacing with a new one or not.

 

thanks

 

I just had this problem yesterday when I was pulling out wiring for the factory amp, defroster, 3rd brake light and a bunch of other creature comforts. Blown fuse is all it was. If I hadn't of found this thread I would have thought it was one of the wires I had cut from the bcm.