2003 Silverado, No Brake Lights

HotRodV6 · April 16, 2008

Ok, well I'm not sure how long they have been out, but the brake lights aren't working on my truck, all the other lights work fine, turn signals both front and rear, and the CHMSL works like it should, but the main lights don't light up when i hit the brakes. The tail lights work fine as well.

I checked the fuses but didn't find anything, and i need to get my truck inspected asap, it went out in Feb, but i purposely waited till march to get it done so the reg and inspection would be the same month, but i got busy moving and forgot to get it done.

Anyways if anybody can give me some things to look at i would sure appreciate it.

HotRodV6 · April 17, 2008

Looking at my Haynes external light wiring diagram, it appears the CHMSL catches a hot right after the brake pedal switch which goes on to the turn signal switch. Turn signal, hazard, and stop light switched hot are determined in the turn signal and feeds from it to each tail light. If you get the steering column covers off and you have 12V on the white wire going into the turn signal with the brake pedal depressed, you most likely have a turn/hazard switch problem. OR a bad connection of the white wire in that plug.

Edit: Also could be the STOP LAMP RELAY under the hood. It may be the same part number as other relays and a quick swap will tell the story.

Thats exactly the infoi i was looking for. Ill check the relay, but im thinking its the multi function switch, as the relays dont go bad all that often, but maybe ill luck out this time.

Thanks again for the help.

hubbycap · April 16, 2008

Looking at my Haynes external light wiring diagram, it appears the CHMSL catches a hot right after the brake pedal switch which goes on to the turn signal switch. Turn signal, hazard, and stop light switched hot are determined in the turn signal and feeds from it to each tail light. If you get the steering column covers off and you have 12V on the white wire going into the turn signal with the brake pedal depressed, you most likely have a turn/hazard switch problem. OR a bad connection of the white wire in that plug.

Edit: Also could be the STOP LAMP RELAY under the hood. It may be the same part number as other relays and a quick swap will tell the story.

HotRodV6 · April 30, 2008

Same thing happened to my 2006 HD, one of the lights stopped working and tried to change the bulb, didn't work so took it in for a checkup and the dealer ended up replacing the whole harness going to that side.

eah i called the dealer today and a new replacement pigtail for the bulb is 21 bucks. i have no idea why GM has such high prices on something that should be so cheap.

HotRodV6 · May 1, 2008

Well went to get the new pigtail, and it turns out its the whole harness for that side, its the only way you can get it. Well it was 23 bucks out the door which isnt to bad for the whole thing. well i get home and change clothes and go out to replace it and i figure its easiest to put all the plugs in the taillight and put the light back in and then run the harness over the chassis junction block. And its then i realized the guy gave me the drivers side harness and i needed the passengers side harness. At least its not that hard to replace.

Ranger · April 29, 2008

Same thing happened to my 2006 HD, one of the lights stopped working and tried to change the bulb, didn't work so took it in for a checkup and the dealer ended up replacing the whole harness going to that side.

sillyazz · April 16, 2008

Ok, well I'm not sure how long they have been out, but the brake lights aren't working on my truck, all the other lights work fine, turn signals both front and rear, and the CHMSL works like it should, but the main lights don't light up when i hit the brakes. The tail lights work fine as well.

I checked the fuses but didn't find anything, and i need to get my truck inspected asap, it went out in Feb, but i purposely waited till march to get it done so the reg and inspection would be the same month, but i got busy moving and forgot to get it done.

Anyways if anybody can give me some things to look at i would sure appreciate it.

Unless both of your brake light bulbs are out, then I would say brake light switch by the brake pedal.

HotRodV6 · April 29, 2008

OK, i wanted to update this, i pulled the covers off the column and checked the wires coming from the switch going into the switch and all was good there. So i decided to go ahead and check the bulbs before i tore the column apart anymore, both bulbs looked ok by looking at the filament, and were alittle black on the glass, i went ahead and replaced them both. The drivers side works now, but the passenger side socket was burned up when i removed the bulb. So i need to replace the socket.

So it looks like i lucked out and dont have to drop the cash for the multifunction switch, but GM is sure proud of the replacement pigtails.

Hope this helps out anybody else.

HotRodV6 · April 16, 2008

Ok, well I'm not sure how long they have been out, but the brake lights aren't working on my truck, all the other lights work fine, turn signals both front and rear, and the CHMSL works like it should, but the main lights don't light up when i hit the brakes. The tail lights work fine as well.

I checked the fuses but didn't find anything, and i need to get my truck inspected asap, it went out in Feb, but i purposely waited till march to get it done so the reg and inspection would be the same month, but i got busy moving and forgot to get it done.

Anyways if anybody can give me some things to look at i would sure appreciate it.

Unless both of your brake light bulbs are out, then I would say brake light switch by the brake pedal.

Well that was my first thought, but since the CHMSL (Center High Mounted Stop Lamp) is working when you hit the pedal, and it gets its feed directly from this switch and doesnt go thru the turn signal switch i have ruled it out.

I recently installed a new clock spring and steering wheel with radio controls, but the stop lamps were working after i got everything back together. I know GM has had problems with the multi function switch, but i want to do some checking before i buy a new switch.