Lights go out when pressing brake pedal

[ssutton]

Hey guys, I tried searching through old posts and couldn't find anything similar to the issue I'm having. So my issue is when I first started the truck, the dash lights and head and tail lights all work but as soon as do anything that seems like it would draw more power, like press the brake pedal, I lose all lighting until I turn off and turn the truck back on.

I recently installed a gauge for my EGT, boost and coolant but the probably didn't start until I recently had my batteries short to the body and blow the fusible link on the firewall. I replaced that with a 60 amp inline fuse and now the truck starts and runs fine again minus this problem.

 

[cucvrus]

My guess is the fuse box 30 amp fuse. Right side of fuse box 1/2 way up. that circuit is a hot spot for lighting issues. The brake lights are served off the same leg in the back of the fuse box. I recommend cutting the circuits and installing 2 in line fuses or a circuit breaker. Not a huge fan of cutting it but unless you want to replace the clips to the fuse box or the wiring harness I see no quicker permanent fix. Good Luck. Be Safe.

 

[ssutton]

My guess is the fuse box 30 amp fuse. Right side of fuse box 1/2 way up. that circuit is a hot spot for lighting issues. The brake lights are served off the same leg in the back of the fuse box. I recommend cutting the circuits and installing 2 in line fuses or a circuit breaker. Not a huge fan of cutting it but unless you want to replace the clips to the fuse box or the wiring harness I see no quicker permanent fix. Good Luck. Be Safe.

There's a good chance that I messed up those pins when checking fuses after the fusible link melted then. Thanks for the idea, I'll check it out.

 

[ssutton]

If anyone sees this thread and is having a similar issue, cucvrs was correct it was an issue with that fuse. Specifically, I have expanded circuit coming off of that fuse using a spade adapter that was keeping the fuse from completely seating back into the holder after I checked it. I tried getting it to stay in again but after about 10 minutes of driving it always vibrated out enough to kill the lighting. I removed the circuit expander and placed the fuse back in but it just does not seat firmly like the other fuses. I may have do what cucvrus was talking about and cut the wires in the back to run inline fuses if the problem arises later on.

 

[Floridianson]

If anyone sees this thread and is having a similar issue, cucvrs was correct it was an issue with that fuse. Specifically, I have expanded circuit coming off of that fuse using a spade adapter that was keeping the fuse from completely seating back into the holder after I checked it. I tried getting it to stay in again but after about 10 minutes of driving it always vibrated out enough to kill the lighting. I removed the circuit expander and placed the fuse back in but it just does not seat firmly like the other fuses. I may have do what cucvrus was talking about and cut the wires in the back to run inline fuses if the problem arises later on.

Thanks for posting what you found and did / will do. I do not have a cucv but members that post a problem and then follow up on what / how and the fix help out other members when it is there turn to have a problem. Wish more members would do the same and follow up on there threads they start. Good job new member.