Jake and fan problems

Tyler '

New Member
I have a 2009 isx 525 cummins that the fan is always staying on and the Jake stopped working.. Any clues
 

Tazz

Infidel
By always do you mean it never shuts off, are you running your AC?

The default for those is if there is a problem to turn on.

Hammer166 Hammer166 might know of a related problem taking out the jakes. I know the fan automatically kicks on when the jakes engage when set to factory settings but this is the opposite so?
 

mndriver

curmudgeon extraordinare
Supporter
If it just started I would not expect it to be in the ECM. Personally I would start with checking all of my grounds and making sure they are clean. Next I would inspect the wiring harness and make sure there isn't a short or an open in the wires.
 

Hammer166

Instigateur №166™
By always do you mean it never shuts off, are you running your AC?

The default for those is if there is a problem to turn on.

Hammer166 Hammer166 might know of a related problem taking out the jakes. I know the fan automatically kicks on when the jakes engage when set to factory settings but this is the opposite so?
All that happens in the ECM, as far as fan on with jakes. Very unlikely to be a problem w/ ECM as there isn't any opposite setting. Not sure where the fan solenoid is on an ISX, but what you need to do is trace back the harnesses from the jakes and the fan until they meet up, your trouble is most likely between that junction and the ECM. Like mndriver mndriver said, check the grounds and for open wires in the harness (usually where the harness is bent around the engine, cab, or frame.)
 

Copperhead

Well-Known Member
The fan is air actuated. If that hose gets a leak somewhere (I have had that happen before), then the fan will stay on all the time by default. But the engine brake, that sounds electrical or ECM.
 

Chybaka

Member
Had the same problem in my old freightliner, the problem was caused by low oil in the engine, thus engine was hot and jakes didn't work.
 
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