Cat C13 Fan does not shut off.

Mine was air conditioner high pressure sensor bad, then had air leak later from hub which I had to replace.

 

four things command the fan to come on.
1. coolant temp.
2. a/c high pressure switch.
3. intake manifold air temp.
4. fan override switch.

 

Another issue is the wiring harness going to the A/C high pressure switch. The high pressure switch is a trigger signal to the ECM to bring the fan on, but what most people don't realize is that it is a ground signal. If the wiring harness to the high pressure switch has rubbed through the insulation and is grounding out to the engine or truck, the ECM will bring the fan on constantly.

You need CAT ET to determine if the ECM is saying that it is getting a signal to turn the fan on from the truck and why

 

I have a 09 W and turn key in on position and air is leaking out of fan hub it has been sporadic I thought there might be a solenoid under hood I changed before or maybe fan clutch is just junk any help would be appreciated

 

If it's leaking air out of the hub the ceramic seal or O rings are gone. Needs a rebuild kit, not a hard job if you've got the right tools.

 

Thank you

 

Im having same issue here lately- And before I start thinking the worst (ECM) Please share a MOST possible Diagnosis to remedy this.

I have a C-12- Fan Comes ON when I hit a Bump or hit the brakes..Not All the time ,And it will shut off sometimes immediately- Sometimes its on for 3-4 hours.....Im Puzzled

Here are the Facts-
1.Newer Fan Hub-installed 2015
2.NO fan override switch in cab
3.Temperature gauge/sensor works perfect
4.A/C Has been removed for better of 10 years
5.I Have NO fuses or relays for engine fan
6.I Have ZERO air leaks at Hub or anywhere for that matter
7.No coolant leaks

Something is making it come on when I Hit a Bump or suddenly slow down...And Yes,It Does shut off,But its Never Known when it does

 

Interesting sounds puzzling did u say no A/C I mean I didn't have air conditioning for most of my 37 years driving but there is no way I could do without it anymore god bless most clutches on trucks I think are air operated but like in my W9 there is a ton of electronics to go with it I wish u luck

 

I had the same problem a few months ago, I was near tearing my hair out. Changed the temp sender on the block, changed Horton solenoid, turned out to be the solenoid triggering wire from temp sender to solenoid was grounding where the insulation had worn through on a stand-off bracket, and when I hit a bump it was enough to ground out and turn the fan on.