Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 6 of 6 Posts

·
Registered
2004 gmc envoy_sle_xuv
Joined
·
10 Posts
Discussion Starter #1 (Edited)
OK.. Sorry if this is a repeat, I could not confirm others were having this same issue.

the Problem.. all of my rear light bulbs work and are lit when the lights are on, lock the truck, etc.. EXCEPT when I press the brake pedal.

I have checked both fuses..
the third brake light comes on when I press the pedal, but not the primary ones.

are these bulbs like a three way bulb that part of it could be bad?

the bulbs are lit when I start the truck and have the lights on, but if I press the pedal they do not get brighter, nor do any lights come on except the third brake light if the truck is off and no lights on..

any ideas ??

THANKS in advance

Side note.. I did just have the dealership replace the rear suspension airbags, could something have been accidently unplugged?

thanks
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
3,250 Posts
Did this start immediately AFTER the trip to the dealer?
 

·
Registered
2004 gmc envoy_sle_xuv
Joined
·
10 Posts
Discussion Starter #3 (Edited)
I am not sure.. I can't see my brake lights when I brake :)
Over the past week a couple associates at work have told me my tail light was out, when I checked the lights they of course worked. I started playing with them last night with a friend to see and sure enough when you press the pedal they do not get brighter and when the lights are not on, they do not come on at all (except the third tailgate light)

Usually I am the last to leave the parking lot, so not uncommon for no one to have said anything earlier..
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,298 Posts
If the third brake light is working, your brake switch is good.

These are two filament lamps. It is possible to have one filament fail, and also
possible for both lamps to fail close to one another (as I discovered a few months
ago).

Start by checking the bulbs. If you;re good with a meter, you can check voltage at
the sockets at the same time. If you have power, that eliminates the voltage supply
as a problem.

If you don't have power, check your lamp circuit boards. The older model boards had
a recall on them, and it's always possible that some have gotten overlooked. You may
find some melting of the sockets, in which case, replace the boards. If you don't see
any problems, check continuity between the pins on the back of the board and the sockets.

That's at least the easiest place to start.

Good Luck!

Chris
 

·
Registered
2004 gmc envoy_sle_xuv
Joined
·
10 Posts
Discussion Starter #5
Just pulled the bulbs, YUP, two filaments.. one is fried.. will be stopping and buying a couple bulbs tonight and replacing all 4 prob, just to be on the safe side :) they come 2 to a pack anyway..

quick question though.. I did forget to check the wattage of the bulbs. I did have an issue with my headlights when I bought the proper replacement bulbs apparently some are 52 w and others are 55 w, the 55 w ended up frying my wiring and I had to replace it.

does the back have the same problem ?

thanks everyone
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
1,298 Posts
As long as you get the 3157 lamps, you'll be good.

I discovered that the previous owner of my truck (or the dealership) put
a 3057 on one side. Never bothered to figure out if there was a load mismatch,
because I swapped both of them out for the 3157 lamps.

Yours should be the same, or close enough to not matter.

Cheers-

Chris
 
1 - 6 of 6 Posts
Top