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98 Jeep Cherokee 4.0 - Electric Radiator Fan???

Posted By: HEMIDARTS

98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 01:46 AM

I have a 1998 Jeep Cherokee. It is not a Grand Cherokee. It is a 4 door with the 4.0 engine. I noticed that my electric fan would not kick on. I checked the motor and it was fryed. I just replaced the whole fan assembly including the motor. I let the jeep get up around 200 degrees. It never kicked on. At what temp should this fan kick on?

When i unplug the temp sender, the fan comes on right away and stays on until i plug it back in.
So it would seem that the fan is working.

Please help me out. Thanks
Posted By: Andrewh

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 02:48 AM

When coolant temperature reaches approximately 103°C (218°F) , or when air conditioning is requested, When coolant temperature drops below approximately 98°C (209°F) , the PCM opens the ground path to the relay. This will prevent the cooling fan from being energized.
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 02:50 AM

Thank you for that answer!
I also noticed that when i cranked on the AC, the fan never kicked on.
Does that mean something?
Posted By: AARCONV

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 03:52 AM

with a/c on it should turn on automatically
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 04:02 AM

Yeah i was disapointed when it the fan never came on after i ran the ac for a minute or 2.
does this mean there is more of a problem since the ac dont kick it on?

this jeep has 256K miles on it, and i use it to plow with.

It was over heating last year with the plow.
Im hoping this year it wont do that now that i replaced the electric fan and motor.
Posted By: Andrewh

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 04:07 AM

check the relay for the fan. See if you bypass it if it comes on, or just swap it with another relay in the group and see if it comes on when the a/c is turned on then.

Or you might have to do some trouble shooting with a meter to figure out where your power is missing.

Odd that it comes on when you unplug it from the temp sensor, could just be a bad temp sensor. But since the a/c doesn't care about the temp, I would lean towards the relay.
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 04:13 AM

Thanks for the advice!
I will have to check the relays.
i just want to make sure when it gets hot, that fan kicks on.
I use it to plow with, and on the highway the plow blocks the airflow!
Posted By: hooziewhatsit

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 04:34 AM

Quote:

Thanks for the advice!
I will have to check the relays.
i just want to make sure when it gets hot, that fan kicks on.
I use it to plow with, and on the highway the plow blocks the airflow!


My '72 W200 has a plow on it as well. With a 180* thermostat, driving around town without the plow, it would sit around 180*. Driving with the plow, it'd hit 210* Hopefully the mercedes fan will fix that.
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 04:40 AM

Quote:

Quote:

Thanks for the advice!
I will have to check the relays.
i just want to make sure when it gets hot, that fan kicks on.
I use it to plow with, and on the highway the plow blocks the airflow!


My '72 W200 has a plow on it as well. With a 180* thermostat, driving around town without the plow, it would sit around 180*. Driving with the plow, it'd hit 210* Hopefully the mercedes fan will fix that.



Yeah i hope both of our fan problems are fixed!
I also installed a 160* thermostat so hopefully everything will work good this year for us both!
Posted By: Andrewh

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 01:46 PM

full text for trouble shooting.

When coolant temperature reaches approximately 103°C (218°F) , or when air conditioning is requested, the powertrain control module (PCM) provides a ground path for the fan relay. This ground is provided to the cooling fan relay through pin C2 of PCM connector C3. Battery voltage is then applied to the fan through the relay. When coolant temperature drops below approximately 98°C (209°F) , the PCM opens the ground path to the relay. This will prevent the cooling fan from being energized.
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 07:13 PM

Thank you for this info!
Posted By: rapom

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/16/10 07:22 PM

I don't think you will need the electric fan in the winter. I also have a 98 4.0 5sp. Jeep cherokee 4x4 and I remove my mechanical fan every fall so basically I run around with no fan. (I live in Northern Oh.) The electric fan would never come on in the winter. But would come on in the fall or spring if I was sitting in line at a Drive through. Electric fan would kick on at about 218 like the everyone says. Just saying that you should never need your electric fan in the winter.

I would also like to add that I have an aftermarket brass 3 core radiator where the factory one is 2 core plastic/ aluminum radiator. I replaced mine because it was plugged.

Attached picture 6304517-July2006005.jpg
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/17/10 01:16 AM

You are probally right about not needing the fan,
but i have a large plow that blocks the whole front of my jeep.
so no air gets in the radiator.
I pegged the gauge 5 times last year when it was 10 below zero.
It always cooled right back off after a minute or 2.
my plow jeep also has over 256,000 miles on it.
Posted By: buildanother

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/17/10 01:40 AM

If it primarily uses a belt driven fan(water pump), I would think about changing clutch unit. I only say that because I drove a service truck for a bus company(old ranger 4x4 plow turd), that would run very hot in below zero weather on a 10 mile highway trip with blade on. Tried running blade at many angles and heights, still got hot fast. Put a new clutch on the stock fan, and not a problem since.
Posted By: HEMIDARTS

Re: 98 Jeep Cherokee 4.0 - Electric Radiator Fan??? - 11/17/10 02:22 AM

Thanks for the idea.
I will check into that later.
I think the relay thing will fix it.
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