No Brake Lights?

Hey,

It could be the turn signal switch, but before you go testing the wiring and connections, try cycling the emergency flashers. What happens is the switch connection get corroded and stop working, when you move the switch it cleans the contacts.

If that doesn't work here are some wiring diagrams and guide to help you get the problem fixed.

https://www.2carpros.com/articles/brake-lights-not-working

and

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester


Please run some tests and get back to us so we can continue helping you and check the blinker wiring diagrams so you can see how the system works.

I had no brake lights at all, yet all other lights work as designed. Resolution to this was to find breakage in the wiring harness between the brake pedal switch and the circuit back to the brake lights. Due to repetitive bending the wire inside the insulation broke and another wore off insulation

Great addition to this thread! Please feel free to help out on the site whenever it can add information that will help.

Good find!

Cheers, Ken

My brake lights went out on my truck. I checked the boards, bulbs, fuses, and replaced the brake light switch, and still no working brake lights. The running lights, hazards, and turn signals works.
My father ran a continuity test, and could not get power to the fuse box in the cab. I looked under the hood, and there is no stop lamp relay.
Is this a ground issue? If so, where is the ground located?
Any help is greatly appreciated!

the ground will be located on the lh side at rear of frame. check to make sure all the pugs are connected at back of frame on lh side as well. if th eturn signals work then it may be the multifunction switch or maybe the trailer connector. check the dark green and yellow wires from multi function switch while applying brake.

Also my taillights just have head lights. When headlight switch is off tail lights work. Put a new headlight switch, brakes switch is good, put all new bulbs.

Hello,

The Daytime Running Lamps Module is probably bad in your vehicle. In the diagrams down below I have included a wiring diagram of the exterior lighting circuits for you vehicle as well as the headlights wiring diagram. As you can see the Daytime Running Lamps Module not only controls the headlights but has outputs to the tail/brake lights as well. I have also included instructions for the removal and installation of the DRL Module in the diagrams down below for you as well. Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

My brake lights have stopped working. All other functions work, running lights, turn signals, just no brake lights. Therefore I am assuming there must be a switch under the dash that the brake pedal depresses that has gone bad. All advice is appreciated.

Good evening,

Yes, there is a switch on the brake pedal under the dash. I attached the procedure and the picture for you to view.

Also, check the fuse listed in the diagrams I sent you for power on both sides.

Roy

1. Disconnect the negative battery cable.
2. Disable the SIR.
3. Remove the pushrod retainer from the brake pedal pin. Use snap ring pliers.
4. Unsnap the stoplamp switch from the pushrod.
5. Disconnect the electrical connector from the stoplamp switch.

So long delay I know it wasn't the brake pedal switch. how do I check the fuse? And, can you think of additional possibilities? I did check to make sure the bulbs were good. ;)

Did you verify power to the switch?

Roy

Nope by the time I figured out how to get the darn thing off I didn't consider that.

Check for power to the switch.

Roy

White tail lights. When my headlights are on or taillights on just the roof light works. changed bulbs sockets are good.

any help with how to do that would be appreciated.

Good afternoon,

Check for power to the stop light switch. I attached a diagram for you to view. Let us verify we have power through the switch.

Roy

Here is a guide for checking a fuse. You need a test light or voltmeter to test the brown wire to the switch.

https://www.2carpros.com/articles/how-a-car-fuse-works

Roy

My lights are new the fuses are good and I am getting power to the harness but the lights do not come on when the pedal is pushed down why

first thing ill ask does the third high rise brake light work? if not chances are the brake switch is bad or misadjusted.

if the lights on then the turn signal switch has failed and you need a new one.

Read this guide on using a test light, it will help

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

The wiring diagrams for your brake lights are attached below

none of the lights work and I have replace3d the brake light switch

next make sure the plunger on the switch is being moved when the pedal is moved, does pushing on switch by hand change anything? check and makesure the third light isnt burned out and recheck for brakes.

you may want to check for damage in the harness inm cab next since all 3 dont work.

The tail lights, turn signal and brake lights do not seem to be working correctly. When I turn the lights on the tail lights lite up. When I step on the brake the driver's side brake light goes out. If I turn the left turn signal on it blinks, but once you step on the brake it does not. We have changed bulbs, fuses and tried to check the wiring but not knowing the wiring schematics makes it difficult.

Hello,

It sounds like you have a fuse out or the hazard/turn signal switch that is not working right. Here is a guide to help you see where you are loosing power:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here are the wiring diagrams for the rear lights, please let me know if you need a larger version.

Check out the diagrams (below).

Please let us know what happens.

Cheers, Ken

I have no brake lights and running lights. when my headlights are on only have headlights with headlights off but taillights are dim but roof light works good. changed bulbs and sockets and I also get a quick flash from turning signals. I asked this taillight question before but this is the whole problem now.

Welcome back.

May I ask if you are using LED bulbs in this?

Rich

Hi, i recently purchased a 1995 gmc yukon. 4dr, 4 wheel dr. My brake lights, hazard light, and license plate lights don't work, everything else does. It also has what appears to be an aftermarket tow hitch. under the hood in the fuse box there is a spot marked stop/hazard light on a 30 amp fuse i believe. However it's not a complete ckt. I took the box apart and there is now wire leading to the the metal pronges like the other fuses. Is it supose to be like this? It makes no sense because i have a schematic that says a fuse is suppose to be there, which it is but . Any help is appreciated

I had the same sort of problems.My third brake light worked but not my two rear lights,also my hazards didn't work.I tried various things ,but what the problem ended up being was my blinker assembly.after replacing it everything worked.....hope this helps

The tail lights don't light up with the headlights on. They work when I push on the brake pedal and the backup lights work. I replaced all the bulbs and put new cicuit boards in and I also checked all the fuses "there good" Then I looked at the wires and nothing seems to be wrong with them. After checking the fuses and wires, replacing the circuit boards and bulbs they still don't turn on when I turn the headlights on. Can you help me?

The brake lites aren't supposed to come on with headlites. Are you talking about tail lites?

The brake lites only come on when you activate the brake switch, step on the brake.

The right hand blinker and right hand brake light does not work I have changed the bulbs and the part that the bulbs fit into.

Good morning.

The power comes from the turn signal switch for the right rear brake and turn.

the first thing I would do is to check for power to the connector. use a test light or voltmeter to verify.
if you have no power then you need to go to the turn signal switch. check the dark green wire from the switch.

Roy

Hi all, wanted to chime in. I just had this issue on my 99 GMC Suburban, 5.7L 4x4.

I went through changing out the switch, tail light boards, bulbs, fuses, etc but did not fix the issue. Finally found a spot to test the voltage for the brake light switch. I was getting 0.7 volts when brake pedal depressed, reading the white wire (brake light control wire). Couldn't find a spot to easily read the voltage for the orange (constant 12v) wire, but could reasonably assume there was an issue with either the brake wire (white) or constant 12v (orange).

The brake light wire harness pigtail is an ~8" section that has another connection opposite the end that plugs into the brake light switch, which connects into the main wire harness for the vehicle under the dash. To access it (more easily), you have to remove the plastic knee cover on the lower dash(4 - 7mm bolts) and disconnect the panel vent (un-clips from the panel and then slides out of vent tubing), then remove the larger of the 2 metal brackets (4 - 10mm bolts). Once that plate is off, there is a large square connector that is bolted onto the console frame with one 7mm bolt. Remove that bolt and lift the connector up and off the bracket to give you more room to maneuver the pigtail out. From there you have to remove the adhesive that holds the pigtail to the frame (I used a long flathead and some pent up aggression to get it to break free), and snake the pigtail down to the front. Be careful to not damage the wires on the metal frame while doing so.

When i removed this and checked the wires, my 12v orange wire was damaged and corroded, I then replaced the pigtail with one I got from pick n pull (like 4$) and my lights worked as they should!

I have seen a bunch of posts saying check the white wire, or it gets pinched in the path up to the multi function switch, but if you have cruise control and function of your multi function (turn signals, hazards, etc) my money is on your wire harness pigtail to the brake switch itself.

When you replace the wire harness, make sure you put on a corrugated wire shield to avoid further damage to the cables.

I hope this helps someone else, as it has been a huge pain for me.

Excellent addition to this thread! Please feel free to use 2CarPros anytime!