Need some advice

BrandonC

Member
Joined
Mar 6, 2013
Location
Morehead City
I have a 2003 Suburban and am having rear brake light problems. When i hit the brake the light works when i am not and just the lights are on it does not. I have replaced the socket and still no luck. I was wondering if anyone else had this problem.
 
Always hard to guess. Most likely, the brake light is looking for a ground and using the lighting hot side circuit for a ground. Once power is applied to the lighting circuit, that circuit becomes hot, and the ground the Brake light was using is gone. May not be at the tail light, although thats the most usual problem area
 
LETS start at the basics.
Have you replaced the bulb?
 
I have replaced build with on that works. The one from the other side changed socket the fuse is getting power but I am not receiving any to the rear socket. There is a junction on the driver rear but I am also not receiving power there either so I was wondering if someone has some locations that they know of with all the info or a schematics I need.
 
Feds should have Demanded a recall on all Suburbans & Chevy vans, for taillight issues. Got to be the Worst vehicles on the road for rear lights. Fix one, the other goes out, No end to their failure!
 
rodney eppes said:
Feds should have Demanded a recall on all Suburbans & Chevy vans, for taillight issues. Got to be the Worst vehicles on the road for rear lights. Fix one, the other goes out, No end to their failure!
Click to expand...
My 03 GMC does the exact same thing. Just wait til the instrument cluster starts causing problems. :shaking:
 
There's a guy on here very skilled, fast, and affordable at IPC repair. As far as tail lights, sounds like a bad ground for the tail light bulbs. When lights are on, there is power thru the filament to the non-existent ground to the other filament with brake light power on = no voltage difference = light goes out when brake is applied. Lights off, it is enough of a ground to light the lamp.
 
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3rd brake light and left rear parking light not working. When i hit the brakes the left rear brake light works when i put a new buld in it same thing was happening i replaced a fuse in the main fuse box up front and replaced the 3rd brake light and the bulb along with the junction box behind pass rear quarter panel still no luck there is a trailer brake package installed on the truck is there certain locations i should check to see if i have power also what power detection tool should i be using i was using a volt meter or should i be using a test light and where and how to test

This is a pain in my ass
 
Merged the two threads together.

Lots of good help here and a couple of pretty smart electrical troublehshooters specifically.

You will get a lot more help if you are a bit slower and more detailed with your problems.
What doesnt work?
Under what condition does it not work?
What bulb did you replace?
Why? Did it test bad?
Which fuse?
Same questions.
When you change a pat without knowing it is bad you actually add more variables and make the problem harder to find. Dont do that.

Assuming you know how to use each a test light and a multimeter will work equally as well for the problem at hand. You say the light isnt working at all. This isnt a low voltage condition then its an on/off issue.
 
Try unplugging the trailer harness T Connector and plug the original harness back in. Especially if you ever tow with it. If that works check your trailer harnesses for shorts and put a new T harness in.
 
Not sure about an 03, but my 99 has a circuit board type system. was giving similar issues. I just replaced the boards and no more issues.
 
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