Rick's Free Auto Repair Advice

No brake lights

Why don’t my brake lights work

Some owners complain of no brake lights in their early 2000 model GM vehicles. The high mount stop light works, but not the brake lights. In addition, the hazard lights may work on the front but not the rear. Also, the rear parking lights work, just not the rear brake lights or hazards.

Here’s how the system works. Power flows to the rear brake lights from the 15A brake fuse located in the right hand instrument panel fuse box. So check the fuse first. From there, power flows to the brake switch on a brown wire. The brake switch is a normally open switch. When you apply the brake, the contacts close and power flows out of the switch on a white wire to a junction block located on the left side of the instrument panel. A white wire carries power from that junction directly to the high mount stop light. But the brake light wire goes into the turn/hazard signal flasher built into the hazard switch. In the “normal” position, power flows right through the flasher and out to the turn signal switch on the brown wire. The brown wire goes through a connector and enters the turn signal switch as a white wire. With the brake applied and turn signals off, you should have power coming into the turn signal switch on the white wire. If you don’t, check the hazard/flasher and check for power coming into it on the white wire from the brake switch and junction block. If you have power coming into the hazard/flasher but no power coming out, replace the hazard flasher. It is a high failure rate item.

Also see this article

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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