brake lights not working

I just brought home my first duece and realized my brake lights aren't working. Just wondering if anyone has some suggestions before I start digging in to it.

Do you have the light switch in one of the 'on' positions? Read the operators TM for more information.

Yeah, I tried with the light switch in all possible settings. I have headlights, turn signals, and rear running lights. Just no brake lights. Probably something simple. I am hoping to get a chance to work on it tomorrow. I figured maybe someone new of a common problem that maybe would save me some time.

Most likly the switch. It's either a hyd one or the newer air presure one. Both are under the truck on the air pack I think. Simple fix, with the right parts.

Thanks, I'll start there. Maybe I will get lucky and just have something unplugged

I agree check the airpack and replace the brake switch.

Unplug the wires from the switch,

connect a 'jumper' wire to both wires,

crawl out from under truck and observe brake lights,

if they are illuminated,

buy and install a new switch.

FYI if you are unfamiliar with the location of the plug for the brakes it is located on the drivers side inside the frame rail. If this connection is loose or the wires are broken you lose your brake lights but everything else will work. I reconnected a broken wire with a wire nut and it's been working fine for 6 months.

Mine doesn't work until the air pressure builds up and the truck is moving. Get someone to follow you down the street and check

When you crawl under the truck to install the jumper, you will either see the switch on the end of the slave cylinder assembly portion of the Air Pack, or else it will be on the side towards the frame of the same assembly.

The hydraulic on is on the end and is activated by pressure in the brake system itself and since you can make the brakes work without air, it will work regardless of air pressure or not.

The air switch, as pointed out abive, located on the side of the slave clynider will only operate the brake lights when you have some air pressure in the system.

A jumper will turn either type of circuit on in terms of the brake lights.

The air operated switch is in my opinion a superior setup as their is no proximity of DOT 5, which is flammable, and electricity as there is in the hydraulic activated switch. Even so, there are thousands of deuces out there with hydraulic brake switches and they manage just fine.

I changed mine over, but that was my choice and I did it when I was rebuilding the airpack and it was pretty easy to make the change when I had the airpack out of the truck.

Hope this is helpful

RL

Turned out to be the switch. It's the type operated by the brake fluid pressure. I just have to order another one, along with a few other small parts I need before I tag and drive it. Thanks guys!