Brakes turn on climate control

I have a 94 gmc 3500C&C when truck is turned off and the brake pedel is depressed the climate control turns on, when the truck is running it looses brake lights or trailer brakes stay on until the truck is turned off and the climate control is played with. i've changed the brake switch, climate control mod, and the trailer brake controller. ( still does it with the controler disconnected) No extra's added to the fuse panel or the truck everything is stock except for brake controller. any idea's????

Did you mount the brake controller to the dash and then this started happening?

No, the brake controller has been on for a while, i've checked to make sure some idiot had not screwed the brake controller into the wiring harness behind the dash and its screwed into the plastic not on any metal supports.

Nothing else is acting up? Do the lights get brighter/dimmer than usual when its acting up? Smell anything burning?

Nothing else is acting up. no smells. nothing else is effected except the climate control when ign is turned off; works fine when ign is on. and no brake lights. but i have done some testing and the signal wire(white) from the brake switch plug is hot 12V when the issue is there. the climate control only seems to have the problem when it is turned off but when its on panel or def. it turns off with the ign. i am clueless and so is my GM dealer

it sounds like a bad ground that is back feeding power. check the trailer light plug and conections for damp or wet dust/mud. is the brake controler required to have a ground to run right. it may have (trailer brake controller) been wired incorrect. check the wire dia, to be sure. 463

the brake controller is wired proper and the wiring to the trailer plug is good and tested out proper, it does it with brake controller disconnected

reset the computer by disconecting the negitive post for 5 mins and check it again. if that fails start looking for a bad or dirty ground connection in the cab. keep on looking we will find the problem! 463

I have reset the ecm, changed the battery and cleaned the cables and installed new terminals. (changed battery due to -35 it just dont got the cca) anyone know where the ground would be??? i have searched but havent found. also looking for a good wiring schem. for a 94 chev C&C dually 4x4 7.4L.