yep replace both the wheel sensor harnesses if you can find em. none available that i can find.

 

Yeah, I'm looking for the harnesses. None of the parts places carry them (oreilly's, autozone, etc). Have not tried the dealer yet, going to see if I can snag a set off a doner car and make sure the wiring is good and swap them out.

I would understand how moisture would make a contact, thus shorting the circuit and making the light come on, however it is the lack of moisture that is making the light come on. I have the ABS brake wiring schematic from shoebox but it does not go into a lot of detail about the parking brake circuit. I don't know if I'm dealing with N/O or N/C switches in the circuit excelt for the brake combo valve being N/O and closing with unequal pressure, but I have verified the switch is open, which leads me to the shorted wiring, but only shorted when it is dry outside...not wet.

 

Go back and reread what I wrote, moisture helping to make proper contact, not creating a short.
This is only a theory mind you, but nothing else makes sense to me.

 

Ahh...I was thinking backwards. Something in the circuit is normally closed. Wet is helping make the contact. Dry is allowing it to open or not make contact, which would indicate a corroded mechanical contact somewhere. I believe the parking brake switch is a mechanical contact. I have checked it before...maybe I will check it again just to make sure. It's onyl got one wire going to it and I have removed that wire before and shorted it to ground, but it did not make any difference in the warning light going on or off. Without a diagram, I'm not sure how that section of the circuit operates.

 

All your harness plugs are contact points to be suspect of. Have you gone over those yet?
Unplug, clean if needed, schmootz it up with dielectric grease, reconnect, and repeat.

 

Yes, I have recently begun going through the wiring on the car, unplugging every harness connector I can find, sanding contacts, etc. I'll find it eventually.

 

Dang, I was hoping this was a common issue too.

 

I recently purchased a 2002 Z28 and I am having abs problems as well. When the light is on my cruise does still work but the brakes act weird when the light is on and I stop hard. The brake system pulsates and i can feel it threw the pedal also I can hear a slight grinding. I was driving the other day on a country road, my abs inop light was off but over pot holes my low trac light would come on and go off again then my abs light came on and the low trac light never came on again.

 

That right there is your pads are worn and your rotors are warped. Get your brake hardware right then start chasing the other issues.

I broke down and purchased a set of factory service manuals (good price and can't beat having the printed manual right in front of you). This brake warning light issue is driving me crazy. One day it's on, the next it is off. Maybe with proper wiring diagrams I can chase this thing down for real.

 

Well thanks for the reply. I should have also noted that when the brake light is not on and i stop hard there is no pulsing or grinding noises. I did look at the pads they are far from worn out, cant really check the warping of the rotors, but I am looking at getting a better set of pads and rotors when money allows.