DD 60s Jake brake comes on by itself.

how long has truck been doing this. did someone just reprogram ecm?

 

All you need is another 12v wire rubbed through and shorting to the jake circuit and they will turn on. Check for rubbed wires.

 

My similar problem was on a Cat, with the Jake switch on, the jakes would come on now and then whenever they felt like it, even though I was still on the fuel pedal. Even did it once going uphill.

A new Throttle Position Sensor (bolts to the pedal in my pete) solved all these issues.

 

Find out out if the roll control alarm is going off, if it has it. The roll control system will operate the jake brakes to reduce speed. And it can short out just like anything else...

 

What is "Roll Control"????

 

Its a wonderful freightliner thing. A lot of new cars have it too, they call it "electronic stability control". It monitors g-forces and first gives a warning message on the dash with a loud alarm, and at high enough g's it will engage the engine brake to reduce speed. Every truck with it i have ever driven has had the sensors WAY too sensitive. My truck even reduced speed on me once, and i wasnt anywhere near rolling over...

But the best part is it always goes off AFTER i straighten out from the turn....great...

 

Is this truck an older KW with the fuse panel down by the clutch pedal?