Pete 379 c15 Engine Brake not working

If it worked fine prior to changing the clutch sensor, make sure you didn’t hook the wires up backwards on the switch.

If it didn’t work prior to changing clutch switch i would start by checking the voltage going to the solenoid.

If you have a power probe or can power the jake head manually, test each head individually to see if your problem is in the engine brake itself or a wiring issue prior to the solenoid.

You could also have an engine brake fuse and an engine brake disable relay, check those as well as the ground connection.

 

When was the last over-head done?

 

Not sure on a 379.

On my Mack it’s located in the fuse panel inside the cab where the flasher and wiper relays are.

I bet it was a pain to change. The clutch is floor mounted on those trucks isn’t it?

 

Doesn’t matter. They will still engage.
First thing to do is remove your valve covers.
Start engine and push each individual button on top of each solenoid with a screw driver or something. This will ensure proper engagement with each solenoid. Next check your voltages with the wires. Hook your voltmeter up and have some rev up and let off the pedal. See if your getting power to each olenoid wire

 

I always test my jakes before I put the valve covers back on my friend