Brake light switch

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Junior760

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Got a 98 GMC Sierra. I changed the brake booster. Installed a new brake light switch and rear lights won’t come on when I press the brake. I can manually move the light switch forward and the brake lights work. Any ideas in how I can fix this. Thanks
 

Junior760

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Switch out-of-adjustment? Is it the "self-adjusting" kind?

If so, re-set the adjustment, then push the brake pedal.

What does the service manual say about replacing the switch?
This is the one I have. Where would you adjust it at.
 

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someotherguy

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No adjustment in GMT400 brake light switches 1994-up. 1988-1993 must be adjusted after install.

Is the switch properly clipped over the pushrod and the fastener in place? Pushrod possibly bent from an extremely hard braking event?

Richard
 

Mbenson1

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I am experiencing this same issue. I replaced my hydro boost unit and replaced the brake light switch. When I clip it onto the push rod, the switch does not work. When I don’t have it clipped onto the push rod, it’ll work sometimes. Did you ever figure out your issue?
 

HotWheelsBurban

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I had to replace this switch on my crew cab, not too long after the hydro boost unit was replaced. My biggest issue other, than just getting under the dashboard, was getting the clip off the pushrod, that holds the switch onto the pushrod.
I watched a few videos on YouTube, about doing this job, before I tackled it. Not much space to work in....one of the suggestions from the videos was to get the switch located on the pushrod and then rotate it down onto the bracket it snaps onto. I did that and it helped.
I was initially not wanting to attempt the job; I don't fit well in the space available to work under the dashboard on these trucks! But I'm glad I was able to figure it out and get it done. This truck was dangerous without brake lights; people in Houston, Texas area don't notice the center high mounted brake light!
Hope this helps....
 

Caman96

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Snaps right off with a long mini screwdriver. Back on is the problem for sure. Had to get my son, his hand was a little smaller to reach in to clip that retainer on. Possibly just a bad part, but with it working on and off(literally), sounds like either something is misaligned or wiring. Did you try holding brake in and moving wire a bit? Probably.
 
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