Hi. I am very close to finding this issue I believe. Since I got the car, I have had the TCS LIGHT illuminated (lit on the dash meaning the car has disabled it). No matter what I do it will not re-engage. No other lights or issues.

I read heavily on this saying it is the stop light circuit open. I have checked all resistance, conditions, voltage at the REAR tail lights and have the following questions. Hopefully someone can answer:

1) I know I am supposed to have voltage to the brake lights when the car is in the ON position (not running) brake pedal NOT depressed. The rear 3057 and 194 bulbs light up with the brake pedal NOT depressed. My question is should the 3rd brake light, LED light up also? I am not getting voltage to that while in this state. If I push on the brake pedal, I get voltage to the 3rd brake light LED and it all illuminates. Is that correct?

2) I have my friends Snap on Ethos Scanner. I also read the brake switch could be the issue but the brake lights work when the pedal is depressed thus why I did not consider it. His scanner tells the condition of the brake switch status. It never moves from OFF even if the brake pedal is depressed or NOT depressed. I would assume when that pedal is pressed the scanner should move from ON to OFF or vice versa. Does anyone have thoughts on that?

I am positive it is one of the 2 issues above. Just looking for other members input. If #1 above is correct (i.e. the 3rd brake light should not come on at the ON position Brake pedal NOT depressed) than I am leaning towards the brake pedal switch.

Any input over the holiday weekend would be greatly appreciated. Thank you!

This is the same issue we were troubleshooting in https://www.gmforum.com/pontiac-168/...ht-off-312000/

, right?

Yes it is. I changed the brake switch with the same result. Does anyone have a wiring diagram for the brake switch they could share?

What?

First, the car does not have to be "on" for the brake lights to work....
Second, you are NOT suppose to have voltage to the brake lights with the pedal NOT depressed....
Third, your brake lights and center stop lamps are in parallel, so ONLY when you DEPRESS THE BRAKE PEDAL(SWITCH), will all your brake lights light up....if it doesn't work like this, there is something very wrong here!

As far as your second scenario goes, is he looking at the TCC brake switch data or the brake light data?