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1997 Jeep Cherokee Cooling Fan Problems


DJ5A's Avatar
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02-12-02, 11:11 AM   #1  
DJ5A
1997 Jeep Cherokee Cooling Fan Problems

Hello Everybody:

I have a 1997 Jeep Cherokee Sport, 6 Cylinder, AC/AT.

The Electric Fan is coming on for about 10 seconds, off for 5 & seconds, Repeating from the minute it is cranked up til you shut it off?

Now it only does it of course when it is on any of the A/C settings (Which I think this is normal) or when it is selected to run defroster or defroster + out the bottom to keep your Feet warm (I do not think this is normal?)

If you select hot air coming out of A/C vents or out at your feet. The fan doesn't come on.

Now it shouldn't be coming on with the Heater Switched on at all should it?

I'm thinking that the fan switch is bad, but the only thing I can find is a Switch very similar to a Temperature Sending unit there at the front of the block where the Hose goes into water jacket housing where the thermostat is located.

This Switch I'm talking about has 2 wires going to it & it LOL Looks like a Fancy High Dollar Temperature Sending Unit Switch (Probably $20 - $40), which is no big deal. Is there a chance that this switch could be Temperature Sending Unit + Fan Controller Switch Combined? I've Looked all around the Radiator the best I could & I do not see any other switch?

BTW: I've fairly well checked over everything & as far as I can tell it's not overheating, Plenty of water in radiator, also Plenty in Water Resevoir, Belt has proper tension & the Fan clutch appears to have little resistance like most other fan clutches do.

Ok, Now that I've wrote my Jeeps Life story in complete detail, Am I right about this switch, If so I'll replace it.

If not could you please Point me in the right Direction?

If you've read this far, you are a Great Person. LOL, I started to click somewhere else myself, Twice?

Thank You for Your Time!!!!!
DJ5A

 
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02-12-02, 11:21 AM   #2  
Joe_F
The defroster uses the A/C compressor in its function (it dehumidifies) so that would trigger the fan.

The A/C would put a load on the cooling system, so that would trigger the fan.

Putting the heat on through the A/C vents is just another way to route heat, nothing more.

Not sure there is an actual problem .

 
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02-12-02, 12:00 PM   #3  
DJ5A
Joe Cool you's fast as lightening! :)

Hello:

Thank you for your fast reply!

>>You Said>The defroster uses the A/C compressor in its function (it dehumidifies) so that would trigger the fan.

The A/C would put a load on the cooling system, so that would trigger the fan.

Putting the heat on through the A/C vents is just another way to route heat, nothing more.

Not sure there is an actual problem<<

What you says makes sense, I can't believe they now use the A/C to dehumidify the warm air, but hey it ain't the 60's either? It was a lot easier back then, you just had to be a good mechanic, now I don't know?

Ok Questions? Please bare with me, my intentions are all good I promise!

Ok, I run hot air through the A/C Vents or out the Floor, the fan does not come on at all. But it still does if I use anything related to the defroster. I understand what you said but...

When the Fan does come on with it set on heat using either defroster alone or defroster + air coming out at floor the fan runs 10 seconds, off 5 seconds continuing this process the whole time. Is it normal for the fan shutting on & off like this?

If it is normal, I'll be quiet, I'll live with it & I Thank you Joe Cool for all your help!!!!!

Thank you for your time!!!!!
DJ5A

 
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02-12-02, 12:24 PM   #4  
Joe_F
The fan comes on when the coolant temperature reaches a certain temperature. It may go on and off at will depending on the engine load and cooling requirements.

If you turn on the heat, you are taking heat AWAY from the engine, hence it runs "cooler". Think about your driver ed courses and what they said, "If the car is overheating, turn on the heat".

Why? Because turning on the heat fries your tuckus, but it draws heat away from the engine and alleviates the overheating.

Actually, using the compressor to defrost is great. I often set the A/C on, put it on cold and use the defrost setting to remove the humidity in the air and clear the windshield. .

Putting on the defroster cycles the A/C compressor, and using the A/C cycles the compressor. That puts more of load on the cooling system, hence most systems kick the fan on automatically to help dispell the heat.

If you are not experiencing any overheating, I think you are OK. Next time you have the coolant flushed, have the mechanic check it out, but I still don't think there's a problem.

 
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02-12-02, 01:06 PM   #5  
mooser1
I believe Joe's right on with this one....a/c compressors also cycle with heat or especially defrost settings to keep the pumps from just sitting idle for 6 months out of the year, circulates the compressor oil to keep everything lubed.....

 
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02-12-02, 02:29 PM   #6  
I'm lost... are we talking about the cooling fan, the AC fan, or the ventilation fan?

 
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02-12-02, 03:06 PM   #7  
mooser1
I see what you mean....I thought it was the radiator fan (electric) but he says fan clutch, drive belt, etc. is fine, so I'm confused also....

 
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02-12-02, 09:15 PM   #8  
Joe_F
He states electric fan, so I assume he meant the cooling fan by the radiator.

If it's a clutch fan, the A/C might put a load on it for the fan clutch to engage perhaps.

 
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02-13-02, 03:25 AM   #9  
Antony W. Serio
Does a Cherokee have an electric cooling fan? It's a RWD truck, so it should have a clutch fan . It sounds like his truck may have both.

 
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02-13-02, 03:43 AM   #10  
Joe_F
RWD doesn't imply it has a clutch fan, although most "old school" type trucks and cars do .

Need more information from the original poster to go from here

 
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