ABS & Brake Light come on and off

[EXT Blazing]

hi i'm having a problem with my abs and brake light, they keep coming on and off with audible chime while driving, this either happens every few seconds or minutes or sometimes it just stays on for the whole the day with just the chime going off once a while, yet the abs and brakes work perfectly fine even when the lights are one i have checked the fluid level and cleaned up the ground under drivers door, and the problem still persists, is there a second ground for ebcm somewhere?

i went to 2 different shops trying to pull codes and both of them couldn't get anything, one of them had snap on scanner and another gm tech 2, one mechanic said theres a short somewhere in the system causing it

also the thing is when ever i connect trailer to the car the lights go off and never come on, until the next start cycle after the trailer has been disconnected

 

[The_Roadie]

Welcome! Intermittent shorts and opens are hard to find, that's for sure. Are you sure you don't have a hair-trigger on your ebrake handle or the brake fluid level switch causing the issue? I suppose not if you're sure it also lights up the ABS lamp.

On the trailer connection - do you mean the trailer lights go out, or the ABS warning lamp? The mechanic couldn't locate it using that as a clue?

 

[EXT Blazing]

when the trailer is connected. the abs light and brake light warning lamps go out on the cluster and stay off until i have disconnected the trailer and shut off the engine and start it again, if i have the trailer connected and start it the lights never come on, i've towed just about 300 miles in the past 4 days with the trailer and not once did they come on while connected, my trailer does have a on board battery and winch and i have the charging wire hooked up in the engine bay, can the trailer possibly throw power back fixing the short?

 

[The_Roadie]

A short would tend to blow fuses. An open circuit might be fixed by backfed power, but it would have to be the most unusual fault for that to be the fix. Pull fuse #32 in the front fuse block that will disable the threaded stud power and see if the behavior changes.

 

[Wooluf1952]

i went to 2 different shops trying to pull codes and both of them couldn't get anything, one of them had snap on scanner and another gm tech 2, one mechanic said theres a short somewhere in the system causing it

They couldn't find any codes? Or they couldn't get the code reader to connect to the truck?
If it's the latter, test fuse #13 under the hood.

 

[EXT Blazing]

they told me no codes where coming up, since it keeps going on and off, anyway thanks for the help so far i'll check everything out with the fuses tomorrow hopefully it will help me track down the problem