Hi. My 1999 blazer is having a weird issue.

if I don’t turn the lights on, I have stop lights, but if I turn the lights on, I have no stop/tail lights.

im hoping it’s a simple bad ground issue somewhere, so if anyone knows where the lights are grounded, or knows exactly what the issue is, I’d really appreciate it so I can drive the thing at night.

 

There are many places throughout the body and frame where the grounds are located along with what are called "splice packs" that join grounding circuits. I have a 1999 service manual so if you can be a bit more specific I might be able to find you some schematics and locating diagrams. Sending you all of them would be pretty hard as that there are so many pages of of these for our Blazers!

 

what specifics do you need?

 

Any other hints as to the circuits at question; e.g. symptoms of the issue in addition to what you have already shared.

 

sadly that’s all there is to go on. If I turn on the lights, I have no stop/tail lights, if I don’t turn the lights on, I have stop lights.

 

OK, I have to run some errands and some other things to do today. I'll see what I can find for you.

 

I have attached the schematics that I think are relevant. They are all interconnected so it gets complicated.

But after looking at them while doing my search for them, I wouldn't be surprised if the issue was the multi-function switch on the column instead of the ground.

The stop lamp circuit is on page 8-229 with the circuit diagrams on pages 8-56, 60, and 62. The ground circuits are on pages 8-441 or 442 depending on your rear gate type. The other pages are pictures of the harnesses.

The upshot is that the multi-function switch controls the filaments of the rear bulbs (two each) to be used as either stop lamps, parking lamps, or turn signals. There is a lot going on in that switch including the hazard lights.

Let me know if you need any more.

Good Luck!

 

brilliant, thank you.