M920 Brake lights wont go off ?

[R Racing]

Picked up my M920 a few days back. Did a light check and all was good. About halfway home the brake lights came on and wouldn't go off. There was no brake drag that I could tell and at a fuel stop felt the drums and nothing was hot. I checked the TM and no luck there and did a search on here. I was thinking possible brake switch? Does anyone have a PN for 1 and were to find 1 at ? and were it might be located on the truck ? Also the truck seems to take forever to build air pressure (10 to 15 + min ) and never seems to get above 90 PSI. There are no detectable leaks and when turned off it will hold the 90 PSI for more than 15 min with no hiss ? is there a air filter to the compressor that could be clogged ? Bad compressor ?

Thank you
Jim

 

[86m1028]

Jim

My m916 did that, check your pedal switch. My truck had been sitting awhile.
Clean it with electrical cleaner, thats all mine took. Also work your blackout switches.
Are you releasing the trailer brake ?

Hope this helps.

 

[Needle]

I had same problem on both 915s. In ended up being the "hand" trailer brake in both cases. It had been moved just enough to put the lights on.

 

[R Racing]

With the blackout switch on all lights are out. no trailer hooked up so I haven't touched the trailer brake release yet. is the switch under the dash ?

Thank you !
Jim

 

[R Racing]

Hi Needle ! Thats possible ! I did bump it a few times ! will try that tomorrow !

Thanks !

 

[86m1028]

I had same problem on both 915s. In ended up being the "hand" trailer brake in both cases. It had been moved just enough to put the lights on.

I didnt know the hand trailer brake would do that....


Thanks again for help with the deuce pics.

 

[jcappeljr]

My 916 was doing the same thing ,it was the hand brake.

 

[cornrichard]

My 915a1 will do this if it sits for a while. There is a plastic brake light switch on the firewall on the engine side that gets stuck. I tap it with the back of a screwdriver and it is good to go. I need to pull it apart and see if I can clean or lube it. Check the handbrake first, It has caused me to pull out much hair in the past.

 

[R Racing]

guys nailed it right on the head !!!!!! Cleaned up the trailer brake assy . And now lights are out and air pressure builds to 115 in 3 min !! I cant believe what a difference !!

THANK YOU !!!!!!!!!!!!!!!!