No brake lights when engine running

[mockspeed88]

I have a 94 k2500. I recently installed a transmission. I do not have brake lights when the motor is running. Everything else works

 

[mockspeed88]

Also noticed this ground is not connected. Passenger side front frame. Where does it connect to?

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[Erin]

Also noticed this ground is not connected. Passenger side front frame. Where does it connect to?

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To firewall or block. Not sure if that’s your brake light problem though. Mine wasn’t connected for years & it didn’t affect my brake lights.

 

[mockspeed88]

Ok. So what could be causing the brake light issue?

 

[GoToGuy]

The braided ground strap is not over a foot long so...I'll go look. That stud on top frame to another stud directly below the heater in out hose on firewall. Use mirror or feel below hoses for stud. Your broken one frame to body. The engine to body also connects there. Faster to just walk outside then open service manual. Good luck.

 

[mockspeed88]

So this could be affecting my brake light issue? My lights work fine with key off. But when the truck is running only my 3rd brake light works. When I hit the brakes my taillights don't light up

 

[GoToGuy]

You have no brakelights at all, just third light on application?

 

[mockspeed88]

When motor is running only 3rd brake light. Key off brake lights work

 

[PlayingWithTBI]

Key off brake lights work

Hmmm - I wonder if it has something to do with your ignition switch wire going to the turn signals? That's the only difference I can think of having to do with your key on/off issue.

 

[mockspeed88]

Yes it perplexes me. The third brake light works regardless. Running lights and turn signals work aswell.