Brake Light Gremilins

[Slowbro]

Okay, first off I have a 2008 QCSB hemi just so we know what's being dealt with. I have very recently discovered a weird issue where the brake lights (NOT the 3rd brake light though) will stick on briefly. If the truck is off, everything seems to work fine, but once you start it and pump the brakes a few times the rear two lights stick on at full brakelight level brightness and the other light functionality disappears. Shut the truck off, and the lights stay on for ~15 seconds (even if doors are locked) and then everything goes back to normal. I have tested the brake pedal sensor and don't think that's the problem. Suspiciously, I tried installing an old 4 pin brake controller yesterday which ended up not working, so I removed it and that's when I first noticed this issue. I think it must have something to do with that darn brake controller, but I don't know what. Any ideas?

 

[Slowbro]

Well sometimes the obvious things to check yield the best solutions. I went out to the truck and started pulling fuses and quickly found a blown one! Fuse 26, 20A "Brake Switch/Center High Mount Stop Light (CHMSL)/Aftermarket CHMSL". I swapped it with a non critical 20A from the center console power outlet and sure enough brakes are behaving normally. Somehow the brake controller must have blown that fuse when I installed it, but luckily it's not a more complicated fix.

 

[MegaMouseGW]

Well sometimes the obvious things to check yield the best solutions. I went out to the truck and started pulling fuses and quickly found a blown one! Fuse 26, 20A "Brake Switch/Center High Mount Stop Light (CHMSL)/Aftermarket CHMSL". I swapped it with a non critical 20A from the center console power outlet and sure enough brakes are behaving normally. Somehow the brake controller must have blown that fuse when I installed it, but luckily it's not a more complicated fix.

The brake controller may be bad, or possibly it was wired up wrong. Check out the wiring first or take your truck to an RV shop and have them check it out. If that is ok then the brake controller is bad and should be chunked in the trash.

 

[Slowbro]

Yup I revisited the wiring diagram and it turns out I had mine soldered together wrong. Oops. That's what I get for just matching colors and not checking Tekonsha's wiring diagram.