My Chevy 4500 cutaway bus has no brake lights. I replaced the cabin fuse (it was blown), but that did not fix it. I've confirmed power to the fuse box. I replaced the brake switch and that didn't work either. It has LED lights and I inspected the connection, all was good. The running lights are in the same bulb and they work. I'm pretty certain the brake lights aren't stuck on because their just not that bright. While it's a chevy cutaway, the bus was built by Champion Bus Inc. I don't know for certain who would have ran the wiring but my only other thought is there might be an in-line fuse somewhere. I'm at my wits end and the next step is to re-wire everything....... I really don't want to do that. Any ideas?

Ps the engine fuse box does not have a brake light fuse listed (although an online search listed #13), all fuses in this box have been checked and good.

 

fuses blow when there's an overload. Measure/inspect the wiring front to back with a meter to locate faults/damage. Schematics can be found online at charm.li or gmupfitter.com

 

I’ve been working on 4500 Savannahs for 20 years, some of the newer models have a relay on the backside of the fuse block. On the inside of the fuse box lid it has relays not shown. That’s because they are built into the bottom side of the block. One is the stop light relay. They are soldered in, so you need to buy the fuse block. Around $150-200. They can’t be replaced. Must by the block. That will fix your brake light problems if you’ve exhausted all the mentioned in your list. Should be 2013-up.

Fuse block

Back side of block , soldered in relays. one is for brake lights k5 I believe.