# 1999 Jeep Grand Cherokee Radiator Fan



## rocke70

Hi,

Recently my 1999 Grand Jeep Cherokee Laredo 4WD overheated and the radiator broke. After changing the radiator we found out that this was caused by a malfunctioning radiator fan. The mechanic stated it could be the relay so I decided to make the change. Thanks to this website I found the relay under the left front light and was able to replace this. However, the fan still did not work properly although the fan seemed to turn very slowly without cooling down the engine. 

I have driven the car to work as the air flow seems to help keep the car cool. However, today the car overheated thanks to traffic and little car movement. Fortunately, the radiator did not break but the upper hose did. I do not know what the problem could be :4-dontkno? What moves the fan? Is it a belt or an electric motor? If it is the motor, how can I check if this works? Could it be the fan itself?

Need Help?!
ray:


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## qldit

Good Evening rocke70, I am not familiar with that particular vehicle, but generally the system works like this....
There is generally a thermal sensor switch located on the radiator, most often near the bottom, (but it may be in one of the water galleries on your machine) this usually operates in the region of 85 degs C, this then normally would operate the fan relay which in turn operates the electric fan.

The electric fan should really run with pretty decent guts and will be hard on fingers if you are in the way, it usually only needs short runs to drop the temperature.

There is generally a second electric fan associated with the airconditioning system, don't confuse which fan is which, the A/C fan should run most times when the A/C is functioning and is not as powerful as the engine cooling fan.

Most often the thermal switch is the problem when vehicles overheat, (provided that the system and thermostat is otherwise operating properly) I would suggest examining the thermal switch system urgently, it is also possible your fan may have a problem in it's motor and is not operating properly .

I can't explain why you are seeing a mediocre operation with it.

I generally identify which switch / sensor is involved and remove and place it in a saucepan of hot water with a meter lead attached and carefully ensure it is operating before the water boils.
Generally the fan switch / sensor only grounds a current path to operate the fan relay.

I hate seeing aluminium clinder-headed vehicles overheat, generally it starts a chain of nasty events.

Cheers, qldit.


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## rocke70

Good Evening Qldit!

Greatly appreciate your recomendation. I will try to check this and get back to your tomorrow with the results! Thank you!

Cheers Mate!
:wave:


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## Blaine B.

www.jeepsunlimited.com
www.jeepin.com

Jeep dedicated forums. Maybe you'll find help there. I own a Cherokee......good luck!


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