Brake lights not coming on

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Angelo

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My brake lights aren't coming on when I press the pedal on a 96 k3500 with the 6.5l diesel. I read there is a brake light "switch" but I've never been in this area of the electrical and don't know where it is and how to test.

Where do I start with a test? When I turn on hazard lights the yellow lights flash but none other come on.
 

HotWheelsBurban

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Check the wiring harness and fuses first, but there is a brake light switch on the linkage of the brake pedal, under the dashboard. It is a big pain in the backside to get to though and the retainer clip is a MF. Don't lose it either! I had to do this on my crew cab, and it was not fun at all.
 

Caman96

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Check the wiring harness and fuses first, but there is a brake light switch on the linkage of the brake pedal, under the dashboard. It is a big pain in the backside to get to though and the retainer clip is a MF. Don't lose it either! I had to do this on my crew cab, and it was not fun at all.
Definitely don’t lose it! When I did my brake booster, that needs to come off. When I went to reassemble, I snapped a new Dorman clip on and clip broke in half. So I snapped the original back on, after re-tweaking it. :D
 

Angelo

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So I got under dash and saw the switch was not set on the brake pedal "lever" tight, and when I depress the switch the lights turn on
 

Angelo

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However when I set the switch tightly on the rod that goes thru it, it is on the "on"/pressed position. Been fiddle fckin with it to get it so that it only pushes when I press the pedal to no avail
 

Angelo

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I replaced my brake booster last year and it appears like the little nub on the end of the rod is what's causing the switch to be pressed if it's installed on the rod, due to clearance. You can see the nub sticking out in the first pic. The second is the switch how i discovered it, and the third is when it's installed all the way on the rod, and the switch is pressed like this. The last 2 pics is of a replacement switch to show how it works. This is in the off position. The only solution I can think of is to remove the brake booster and grind off this little nub on the end. When I Google brake booster, I saw some with a more pronounced nub and some with a smaller nub on the end. Anyone know of a better solution?
 
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