'78 K20 brake light WTF?

[Minnesota]

Hey guys,

Haven't been on here forever. Working on a 1978 K20 and redid the brake booster and master and now the brake lights are always on.

I've been up and down this thing and I see no switches or wiring at all that was part of this process. There is one brown that goes into the brake proportioner, but that doesn't change anything. There's obviously gotta be a switch somewhere, but darned if I can see anything.

WTF am I missing here?

 

[dremu]

There's a cylindrical pushbutton switch for the brake lights, above the brake pedal, purple and black wires if memory serves.

The switch is adjustable, so if your new booster linkage isn't quite as long the pedal may not be closing the switch. Adjust the switch down until it closes appropriately.

-- A

 

[Minnesota]

Right!? I keep looking. Do you recall if it's passenger or driver's side of the pedal? Auto truck.

Also, I thought it was a pushrod issue off the pedal, so disconnected totally, and jammed the pedal fully away from the firewall. Fricken lights were still on.

 

[blazer74]

Follow the pedal up, probably pushed the switch out of the bracket some or all

 

[blazer74]

 

[Minnesota]

Ok! Thanks guys. I'm really tall so it's hard for me to even fit, but those pics have me bundling back up with a headlamp. I refuse to believe that it's that complex.

 

[blazer74]

Take the metal cover off below the column

 

[Minnesota]

Thanks guys. Got it. I couldn't fit to see, but I hadn't put the "safety bracket" thing back on, which of course also depresses the switch. Add it to the list of things I now know.

 

[dremu]

Thanks guys. Got it. I couldn't fit to see, but I hadn't put the "safety bracket" thing back on, which of course also depresses the switch. Add it to the list of things I now know.

Shoulda thought to post that, as its function isn't immediately obvious if the lever is just flopping loose.

I find that when troubleshooting my truck, Occam's Razor applies. Basically, if in doubt, the *simplest* problem is most likely the case

-- A