O/D Off comes on with Brakes

[Bedrck47]

When you get it home and are parked. Disconnect the Brake peddle position switch connector. Turn the engine on and activate the O/D so that the light comes on. Then press the brakes to see if the light comes on and off etc.

I would not suggest driving the expy on the road with the switch disconnected as you will not have brake lights.

After you do this test reconnect the switch connector

 

[hwheatthins]

When you get it home and are parked. Disconnect the Brake peddle position switch connector. Turn the engine on and activate the O/D so that the light comes on. Then press the brakes to see if the light comes on and off etc.

I would not suggest driving the expy on the road with the switch disconnected as you will not have brake lights.

After you do this test reconnect the switch connector

How do I disconnect it? At the fuse panel? or is there a physical plug i should be looking for?

 

[Bedrck47]

the switch is mounted at the brake pedal and is connected by a plug in connector

You could just remove fuse #5 but that would also cause a loss of power to other circuits. And again DO NOT Drive the expy out on the roads as you will not have brake lights until everything is reconnected

 

[Bedrck47]

Also try what stamp suggested by tilting the steering wheel You can do that before you head home tonight and then try the O/D while driving and braking

 

[Stanger4Life]

As everyone else has stated, sounds electrical since you can do it without the car moving or anything. Has to be a faulty switch or a short in the wiring. Good thing is that it sounds like fix that should be inexpensive and easy. If you need help finding the brake switch I can send you a picture later tonight if nobody can.

 

[hwheatthins]

EDIT: Thank you to everyone who contributed!

So i ended up taking it to the dealership after several hours spent trying to diagnose the issue myself. Turns out the previous owner had an after market alarm system / remote start installed and had done a really poor job with the installation.

Water is somehow getting into the truck and was essentially dripping on the bare wires and causing the O/D to be tied to the braking system.

So problem 1 solved after $200 at the dealership.

On to the next issue --> water getting into the truck. I live the Seattle where it rains a fairly decent amount so i need to get this resolved ASAP.

 

[Stanger4Life]

EDIT: Thank you to everyone who contributed!

So i ended up taking it to the dealership after several hours spent trying to diagnose the issue myself. Turns out the previous owner had an after market alarm system / remote start installed and had done a really poor job with the installation.

Water is somehow getting into the truck and was essentially dripping on the bare wires and causing the O/D to be tied to the braking system.

So problem 1 solved after $200 at the dealership.

On to the next issue --> water getting into the truck. I live the Seattle where it rains a fairly decent amount so i need to get this resolved ASAP.

Didn't even realize you lived in Washington, same here.

Glad you got it solved! I hate shorts in wiring so frustrating! Hey anytime you need some help, PM me. I'll see what I can do.