2nd Gen Non-Engine/Transmission Cummins Exhaust Brake Troubleshooting

[jeepullr]

The original owner installed or had installed a Cummins Exhaust Brake. The brake has been working fine in the month or so I've owned this truck. Yesterday it didn't work, at all. When I hit the button, the light comes on, but there is no noise (hissing) when it's not actuated and there is no braking.



I've run all through the lines, looked as best I could at the vacume lines, all the plugs (even the 2 on the back of the switch) are plugged solid and have no corrosion, the 10A fuse is good, the microswitch on the throttle cable is adjusted correctly... Where should I be looking next? Any trouble shooting guides or tips?

 

[cap-n-cray]

What year is your truck, 6 speed? Was the engine down to idle? If the engine is not fully defueled, at idle, the exhaust brake will not work. My brake occasionally does not work after a long trip. I think it is the TPS over heated. The engine does not defuel or will not go down to full idle. If I turn the engine off for a minute or two it works again when restarted.



Cary

 

[jmeehan]

It might be the solenoid. It gets gummy, but it's easy to disassemble and clean. Mine acted up after I washed my engine once.

There are instructions, but you'll have to do a search on here.

 

[jeepullr]

96, 5 speed



all the way at idle, can even press on the microswitch "button" with no change.

 

[cap-n-cray]

Forget what I said. My E-Brake is controlled by the trucks computer off pin 50 not a micro switch. I would look at the solenoid like jmeehan said.



Cary

 

[nps]

4 things to check:



1. 12V at solenoid when at idle.

2. Good ground to solenoid. Don't assume it's good.

3. Good vacuum at solenoid inlet.

4. Good vacuum to actuator motor at solenoid outlet.



If 1 is bad, you have a power problem.

If 2 is bad, you have a ground problem.

If 3 is bad, you have a vacuum pump problem.

If 4 is bad, you have a bad solenoid.

If 1-4 is good, you have a stuck butterfly or bad actuator motor.



Hope this helps.

 

[Shelby Griggs]

Forget what I said. My E-Brake is controlled by the trucks computer off pin 50 not a micro switch. I would look at the solenoid like jmeehan said.



Cary

I had this problem on my 2001. 5, there is an updated TPS that fixes this, mine was done on D/C's nickle, they are around $400.



SHG