M925 Brake Light

[Piper Cub]

About a month and a half ago, I got my first military truck, an M925! After waiting for the SF-97, getting it insured, and registered, I was ready to take it for its maiden voyage. Before leaving everything was carefully looked over, and everything worked, including the lights. While driving around for a few hours, everything seemed to work pretty good.

After returning home the left brake light doesn't work anymore. The turn signal works, the taillight works, and the right brake light works. I searched in the TM and found the stoplight switch could be the problem. Looking at the one on the truck and trying to follow the wires, everything looks good and seems to have good connections. Any ideas?

 

[Derrickl112]

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[Piper Cub]

The bulb is good.

 

[1 Patriot-of-many]

I would think if the stop light switch was bad, both would not work. Did you change the bulb/test it or just look at it and declare it good?

 

[wheelspinner]

Troubleshooting 101. Do you have power at the last connection prior to the bulb? If yes, its the bulb or fixture. If no, its the wiring between the last place it splits from the other side and where you tested, Thats it, its that simple.

 

[M35A2-AZ]

Just start working back down the wires.
BUT, If the turn signal works, I am thinking it maybe the turn signal switch on the steering column.
Take it apart and clean it lube it with some dielectric. grease.

I think the stop light runs thought the turn signal switch, but I am not sure and can not remember.

 

[Suprman]

I believe there is a brake light switch that works on air you would have to check the tm though

 

[Piper Cub]

The bulb is the same as the turn signal, which works. Tomorrow I'll get out the multi-meter and start testing connections starting at the taillight. Thanks for the help!

 

[wheelspinner]

The bulb is the same as the turn signal, which works. Tomorrow I'll get out the multi-meter and start testing connections starting at the taillight. Thanks for the help!

It may be the same but they are double filament, and one can fail and the other be fine. Swap the bulb from the other side or pick up a new one at NAPA, be sure to specify 24V.

 

[Piper Cub]

I swapped the bulb with the one on the right, and it is good. I checked the turn signal switch, the brake light does run through it and I'm pretty sure that the switch is broke. I cleaned the connections in it and now the green light for the turn signals doesn't come on. I'm going to get a new turn signal switch, so hopefully that will fix everything.

 

[Piper Cub]

I installed a new turn signal switch from Erik's Military Surplus today, and now everything works exactly how it should again. Thanks for the help!