Cooling Fan Inop

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Shea454

NAXJA Forum User

Location

damascus,md

• May 5, 2009

• #1

my cooling fan will not turn on at all. i have a 1991 cherokee 4.0

here is what i tested
my fuse is ok
i swapped relays
i have power going to my relay in 2 places. 1 and 2
i jumped the the relay and my fan comes on
i relpaced my ECT sensor
disconected my ECM and grounded pin31 and the fan turned on

any ideas?

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• May 5, 2009

• #2

Won't come on with the a/c is sometimes low freon.

Wont' come on until about 220+ degrees for heat.

 

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Shea454

NAXJA Forum User

Location

damascus,md

• May 5, 2009

• #3

i have a 3 core radiator, and when i off road it gets to a high temp but never in the red. the fan still does not come on.

i don't have A/C anymore

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• May 5, 2009

• #4

Not sure, maybe you need to jumper the missing a/c system low freon harness, but I am pretty sure that it should run regardless of the a/c wiring when the temperature is high enough.

You could just wire in a dash command switch and run it as needed.

 

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Shea454

NAXJA Forum User

Location

damascus,md

• May 5, 2009

• #5

joe_peters said:

You could just wire in a dash command switch and run it as needed.

Click to expand...

yea, thats what i was about to do at this point lol

 

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winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• May 5, 2009

• #6

Seems like you could just run a manual switch jump the pressure sensing switch connector that used to be on your AC accum/filter before you removed the AC. I think your model has a seperate temp sensor that runs the fan also. You can jump that and make the fan run or check it with a ohmeter, to see if you should replace that (or fix the connection).