I noticed the passenger side headlight isout both the low and high beam. This type of headlight is in one casing but has 2 bulbs with 2 separate pigtails to each bulb. I've not had it happen before where both were out at the same time.

 

ground wire, fuse ect.

 

Thanks, seems like a fuse would affect both driver and passenger no? Or is there an in-line fuse that goes to each light.

Where would I check for a ground issue on one side?

Thanks again,
B

 

I believe the passenger side, and drivers side have their own separate fuses.. on second gens. where they are located, someone on here with a second gen will be able to chime in on this one

as for the grounds for the headlights usually are attached to the core support, or the inner fender

 

We need to know year and model, (pick up, Blazer, Jimmy, Bravada) and if it has the ZR2 option or not, (wiring is different). Headlamp ground circuits are isolated and go through the multifunction switch and are ultimately grounded by the BCM, (Body Control Module). Check the fuses in the underhood fuse panel, (left & right are fused separately) and swap the bulbs with the other side to be sure they are good. If the bulbs are good, the circuits will need to be traced to locate the problem, which we can help you with.

 

so second gens are grounded through the bcm, and not on the core support.. learn sumfin new every day.

 

Yeah, it's a pretty "unique" (to say the least) set up. The ground circuits actually run through, and are spliced at a bus bar, in the underhood fuse panel. The "flash to pass" feature presents some interesting "obstacles", along with DRL's, (Daytime Running Lights) using the high beams at a reduced voltage. They can be a real pita to diagnose without a schematic. And as if that's not bad enough, the ZR2 is different from standard.

 

Yikes, screw that, I will stick with my first gen, that sounds like a mess.

 

Hey Guys, thanks for the suggestions so far.

I failed to mention that this is not for my 1999 Blazer but for a 1997 Suburban that I have. I figured being a GM and similar headlights the wiring would be very similar.

Any input on the Suburban would help.
Thanks,
B

 

If both bulbs are good on the right side, and they both quit at the same time, most likely there's a bad ground. They share a common ground so you can check resistance at the sockets. Remove both bulbs and check resistance from the ground terminals in the sockets, to battery negative, it must be 5 ohms or less. Post your results.