Hi,
The small fan works all time! It should work when the eng. is hot. I got it for computer checking. They said that the problem in the temp. sensor, I replaced it, but the problem is there.
Could you please help?

 

we can't help you if we don't know the year, model and engine of your jeep. Please provide some more information on it, so we can better help you

 

It looks like has a 2001 Cherokee based on his profile.

Have you confirmed that the fan itself is working properly? I usually use take the fan out of the car and hook it directly to a battery to see if the fan motor is good.

Additionally, there is a fan relay in the fusebox in the engine-bay. You could try replacing it with a new one to see if it fixes the electric fan.

Here is some more info on the stock electronic fan;
http://www.angelfire.com/my/fan/electric.html


And worst case scenario, just wire the fan manually like this;
https://www.cherokeeforum.com/f51/el...switch-132465/

Hope that helps!

 

Some confusion here.

By "small fan," do you mean the electric fan mounted to the back of the radiator?

By "computer checking," do you mean you got a check engine light and a code? (If so, post the code here.)

Some info that may help you: In the 2001 Cherokee, the electric fan is supposed to run in the following situations (note that this is different from 1999 and earlier):

1. The coolant temperature reaches 221° F. It's then supposed to stop running when the temperature drops to 217° F.

2. The high side of the air conditioner reaches a certain pressure. This happens regardless of the coolant temperature.

This means that in addition to the temperature sensor, you also have a pressure sensor on the A/C system that may be bad, in addition to the normal relays and grounds. Or your A/C system could be overcharged. Or you could have a wiring issue that is making the computer think either your A/C sensor or your temp sensor is reading high.

Just some ideas to get you started.

 

Many thanks,
it's 2001, cherokee sport, 4.0

 

Many thanks,
the fan is new, the relay is ok.

 

Many thanks,
yes, it's the electric fan. I got it checked on copmputer, but i dont have the code!
I dont undrstand point 2 above, and it's the first time i hear about tne pressure sensor on the A/C system! Could you pliz provide a photo of it?

 

I'm very tired because of this problem. An electrician said that he is going to connect a Nissan Maxima relay with other relay to solve this problem. Well, I don't understand electrical issues very well ...

 

Fan will come on when ac head pressure gets too high by a different switch maybe its bad ? Autozone mt1199.

 

Thanks, can I see a photo of the ac head ?