My brake lights do not work when I press the brake pedal. They also do not work, when I turn on the hazard switch. They do not work when I use the turn signals, either. They do work, when the headligh

You didn't say what you're working on but check at the brake light switch at the top of the brake pedal. There should be current on one terminal and the other has no current until the pedal is pressed if that's OK jiggle the hazard switch to see if that helps, the brake lights go through the hazard switch to the turn signal switch then to the rear lights. I hope this helps. Take care.

WHEN YOU APPLY BRAKE PEDAL, do you see brake lights come on ? if no then the switch is not working fine ! switch turns lights on when you depress the pedal, releasing the plunger, lights go out when you release the pedal. this switch has a fuse @ fuse block. check it ! if ok, and brake lights do
not come on replace switch, & mount properly in bracket.

Yes, if your turn signals in the back use the same filaments as the brakes, the multi-switch must allow the brake signal through when the turn signals are not activated. There are multiple diagrams for your system, so I'm not sure what you have. If you have the light blue wire that goes from the brake switch ul the column to the turn switch, make sure it is getting power when the pedal is pressed. It should go thru the switch as shown in the second diagram below.

brake light dont have relay only fuse brakes are hot at all times on gms. in goes from fuse to brake pedal switch to hazard turn signal switch then to brake lights. ck fuse if good go to pedal switch if good go to turn /hazard switch the turn signal hazard brake all use same wire to lamps.

Its a faulty turn signal switch.Try this,push down and hold brake pedal while pushing on the hazard switch and if the brake lights come on then replace the signal switch.

Can you just check to make sure the ignition key switch is not staying over to far and not backing off when you try to start it. I had a truck that did that and it messed up my turn signals until I brought the key switch back a little after starting it. Just a simple idea. Be kind with your rating for me. Raz

I could not tell you how many times people have brought their cars into my shop and tell me that they had already checked all fues and they are OK, then I check the car and find a blown fuse or a fuse that is completely missing.

Your dash (Instrument Cluster) illumination lights are powered by the "PARK LP" fuse in the underhood fuse panel - it is fuse number 37 and should be a 20 Amp fuse. If this fuse is blown, your Park lights on the exterior of the car will also not be working. If they are working and your dash lights are not, then the problem is probably in your headlamp switch.

Your Brake lights are powered by the "STOP LAMP" fuse in the instrument panel (IP) fuse block it is a 15 Amp fuse.

Your Hazzard lights are powered by the "HAZZARD" fuse in the (IP) also a 15 Ap fuse.

If both of these fuses are good, then the most likely problem with your brake and hazzard lamps is the multifunction (Turn Signal) switch.

What any of the above has to do with replacing your window regulators remains a mystery.

It is not the brake switch as the third light works. If the lights work when the hazard lights are on then it is the turn signal switch. If not then I would check the bulbs and then the relay and fuses.

There is brake light switch located under the dash. It is inserted in a metal bracket that is a part of the brake pedal assembly. When you depress the brake pedal the pedal arm moves away from the brake switch allowing a spring loaded plunger to move out of the switch. As the plunger moves out of the switch a set of contacts close in the switch and turn the brake lights on.

You stated the 10amp under hood brake light fuse is good so check to see if you have power on the "orange" wire at the brake switch with pedal all the way up. Then press the pedal down and you should have power on the " light blue" wire going out of the switch.

We will start there, let me know what you find.
Regards,

Ok you checked for power on both sides of the brake light switch? and you have power on both wires with the brake pedal pressed? and no brake lights? there is a wire broke somewhere between then brake light switch and the lights.
make sure the hazard switch is turned off completely because the brake lights run through the turn signal/hazard switch.