Power on the brake lights runs thru the turn signal switch. This allows the turn signal to take over in the case that you're braking and making a turn also. It sounds like you have a faulty switch or a bare wire in the steering column to me. But keep in mind, I'm not a mechanic and am new to Bowties.

 

All three brake lights stopped working on my 03 Trailblazer. After checking the bulbs and fuses, I concluded it was probably the brake light switch.

The switch looks 100% fine, and when I plugged the wiring harness back onto the switch and manually manipulated the switch, it operated the brake lights fine.

Before pulling the switch, I listened closely, and could hear it operating when pushing the brake pedal.

A picture of the switch is attached. Any idea what could be wrong with it, or wasn't working right while installed on the brake pedal? Anyone else replaced a perfectly fine looking switch and have that solve their problem?

BTW, the brake light contact is the right-most contact (normally open), and the orange wire is always live with 12-volts as described by shawnvw earlier.

Thanks, Karl

 

There are RECALLS for some Chevy TRAILBLAZERS that are related to BRAKE LIGHTS (Turn Signal Switch and Stop Lamp Assembly). Go to MOTOR TREND web site and go to Used Cars > Recalls > Chevy > Trailblazer.

 

@Extra Email: Thank-you for the recall resource! There was a recall for the bulbs coming loose in the tail light assembly, but nothing for the switch.

The brake light switch has operated fine for two months since my post #12. I suspect the contacts of the connector to the switch may have lost electrical contact (since I could hear the switch click when manipulating it prior to removing it).

I didn't realize it, but the brake light switch also (logically so) interfaces with the cruise control, and it must satisfy a setting for the cruise control to actuate. My cruise control had quit and started working again, and I now realize this was a symptom of the brake light switch failing.

 

This happened to me on my 07 TB when a driver flagged me while driving, to tell me I had no brake lights. drove right to parts store. Turned out to be the brake light switch. Never replaced one but it was easy, once I was able to pop off the retaining clip connecting the switch to the brake pedal. But after reading this string, I wonder if it wasnt bad and just needed to be reconnected? I will save old one in case this becomes a frequent event.

 

I have a 2--1 Chevy Blazer, 4.3L V6-Vortec, 4x4. My tail lights work and turn signals work, my fuses are fine, and I just changed my brake light switch and to no avail. Brake lights still wont work. Any ideas?