Engine Fan Staying On...

is it staying on because you have the a/c on most of the time? if so change the fan switch on top of the rad on a/c line going to condensor, if not try a diff rocker switch, then if that doesnt change it, try a fan solenoid, they are known to stick open. 1 way to check is take air line going into solenoid make sure it is getting air in, then take out line off and see if it is getting air out when you turn key switch to on position. (most times when you turn key on or off you can here the air goin into or exhausting out of the fan clutch, but if you cant here it, then try taking the lines off the solenoid to check)

 

the best thing is take it to the dealer have them hook it up and see why the ecm is holding the fan on. The ecm sends power to the solenoid to shut the fan off. Dont rule out the a/c if the expansion valve gets pluged it will hold pressure for a long time which can keep the fan on.

 

You could have a bad high press switch on the A/C. Thats the swtich that will turn the fan on when the A/C is on and say your not moving to get air flow. Unplug the swtich and put a jumper wire on it and if the fan stops you found your porblem. They can go bad and make the fan stay on even with the A/C off.

 

I had a loose wire on the a/c freon temp relay. I gave it a little tug and it came out. Check all the a/c plugs.

 

When my father's Horton fan drive on his '07 started running for no reason, we got it to a shop and it was the fan drive itself that had failed. The bearings were about to dump the fan into the radiator and there was a cone shaped piece of the engagement system that had failed as well causing the fan to stay on all or nearly all the time.

The fan was rebuilt at that time. The piece that broke was something that the shop at KW never had been observed as failing, so parts had to ship or get stolen from another hub. It's probably not really likely, but its a shot.

 

There are two high pressure switches, one to cut out the compressor and the other to signal the ECM to turn on the fan. Open circuit to the ECM means high pressure, once you jump it to trigger low pressure,(assuming the pressure is faulty), the ECM will count down about 2 to 3 minutes before it will actually turn off the fan. This is to prevent over usage of the fan clutch. All this can be monitored with the computer if you take it in.

 

I have 2000 Pete 379 cat 3406 E 475 hp. when I am going up hills with heavy load I am putting on my fan manually to keep engine temp cool .( AC is on or off )is it a good thing to do ? am I demaging anything? Thanks