5 ton Brake Light

My M51A2 brake lights work, but the brakes will not turn them on. I haven't been able to track down a switch.

What signals the brake lights to come on when hitting brakes?

There are two types of switches, one hydraulic, the other air. Whichever switch you have will be under the cab by the master cylinder/ air pack. Without going back and looking, I think the ones that worked off brake fluid pressure were replaced later with ones that worked from air pressure. Something about when the brake fluid ones failed/ leaked it would cause loss of brakes.

Both switches have two connectors. Once you find the switch it is a simple matter of using a volt meter to check for voltage while soldier B presses on the brake pedal.

Scrounge, thanks for the reply.

I found the brake lights switch. It seemed ok, so I started tracking the wire back to the cab. It was cut near the cab. Had to add a little bit of wire, but works properly now.

Thanks