no brake lights on 98 K1500

[Bikerjw]

Hello,
Hoping someone has some ideas.
Just found out yesterday my brake lights are not working.
Including the cyclops brake light at the rear of the cab.
Replaced one of the bulbs there just in case they were burned out...

1 week ago I was towing an old trailer (with lights hooked up).
Don't know if that had anything to do with it, but I did disconnect the trailer wiring harness just in case - no difference.

Running lights, turn signals and 4-way flashers still work. The fuse in the dash for the brake is good (I even verified by swapping with the radio fuse)

I replaced the brake relay in the fuse box under the hood.

The bulbs in the rear light panels are good. I verified by switching them around (since the running lights and signals still work)

the harness to the brake switch appears to be attached well.
And, I assume the switch is working since it does disengage the cruise (and also drops the tranny out of overdrive)

Anyone have an idea??
Thanks,
Jon

[Jeremy-WI]

There is a stoplamps fuse under the hood that you could check, but I don't think that would be the reason that the third brake light(one on the cab) would not work, since most vehicles power the third brake light directly from the brake fuse

[Bikerjw]

yes, there is a stop/hazard fuse there.
I verified it is working - the hazards do not work when I take it out.

Is there a possibility the brake pedal switch is bad, even though the cruise disengages like it should?

[Bikerjw]

have brake lights now after replacing the switch on the brake pedal.
(very hard to get at, and the retaining clip is a bear to get off)

did a post-mortem on the cheap switch:

the switch is multi-function
meaning, there are 3 contacts inside of it
the cruise disengage CAN still work even if the brake light part does not.