M923A2 Brake lights

[Blarsen]

I won a trailer form IP and after we plugged it into my truck we found that the wire under the trailer had been damaged and it caused my truck brake lights to stop working (all other lights work) I have looked at the TM's and cant find a Breaker or Fuse for that circuit, is there one? or have a shorted out my brake light switch?
thanks in advance
Bret

 

[The HUlk]

I doubt it is your brake light switch as it connects to the main light switch, unless it was going bad before the shorting event. Have a look at the field maint. manuals in the link below for troubleshooting procedures...

http://www.steelsoldiers.com/showthread.php?121487-TMs-for-M939-Series-Trucks

 

[Blarsen]

Hulk
I have read both of those and it shows no fuse/breaker for the stoplight circuit at all, just to check the brake light switch and main light controller. I would think it has to have a fuse/breaker in there someplace, but they forgot to list it.

 

[The HUlk]

I would think it has to have a fuse/breaker in there someplace, but they forgot to list it.

As crazy as it sounds there is no fuse or circuit breaker for the brake lights specifically. There are only four or five circuit breakers for the entire vehicle! The wiring diagram is at back of field maint. manual part 5. There should also be a section in one of the field maint. manuals that addresses no stop lamp condition. Check the table of contents in part 1 to find it.

 

[porkysplace]

Hulk
I have read both of those and it shows no fuse/breaker for the stoplight circuit at all, just to check the brake light switch and main light controller. I would think it has to have a fuse/breaker in there someplace, but they forgot to list it.

There should be a circut breaker to 3 lever light switch , the brake lights get power through that switch . Check for power to the brake light switch , if no power there check 3-way light switch.

 

[porkysplace]

Any updates ? did you get the problem fixed ?

 

[Blarsen]

I purchased a new brake/pressure switch, when I get it installed i will give an update.
thanks

 

[The HUlk]

I purchased a new brake/pressure switch, when I get it installed i will give an update.
thanks

You can disconnect the current brake pressure switch & jump the two wires together to determine if the switch is NG fyi. With the light switch in Ser. Drv. position the brake lights should come on when the wires are jumped.