Fan Control Relay missing
#1
Newbie
Thread Starter
Fan Control Relay missing
My daughters 2004 Grand Cherokee has been over heating randomly when idling. The temperature sending unit and thermostat have been replaced. Still no solution. I read on CF about others with similar problems. I also read on here about the fan control relay possibly being bad and started into that task. Removed the headlight, cut the hole and walla!! NOTHING!! The holes are there where the controller should mount but nothing is in the area. (see photo) I have looked around under and over the whole area and can't find it. It is not another style located in the fuse compartment under the hood. Is there another area where I can look? Any help would be appreciated. Ron
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Gary Somers (03-27-2020)
#3
where you able to locate the fan control relay
Where you able to locate the fan control relay. I have the same situation on a 2004 grand cherokee 4.0 liter. Please advise. Thank you
My daughters 2004 Grand Cherokee has been over heating randomly when idling. The temperature sending unit and thermostat have been replaced. Still no solution. I read on CF about others with similar problems. I also read on here about the fan control relay possibly being bad and started into that task. Removed the headlight, cut the hole and walla!! NOTHING!! The holes are there where the controller should mount but nothing is in the area. (see photo) I have looked around under and over the whole area and can't find it. It is not another style located in the fuse compartment under the hood. Is there another area where I can look? Any help would be appreciated. Ron
#4
Newbie
Thread Starter
It took some time but I finally found the solution. I was barking up the wrong tree. It turned out to be low coolant. This particular engine has an unusual way of getting the cooling system filled. On the drivers side of the engine, just aft of the upper radiator hose connection on the top of the engine, there is an allen plug that needs to be removed and the engine finished filling with coolant. After the engine has cooled off I remove the radiator cap before removing the plug. (keeps it from spewing hot fluid all over). Leave the radiator cap off while filling the hole with coolant so you can see when the system is full. There must be a very slow leak in the system somewhere because I need to do this about every six months or so. Whenever the engine temperature gauge starts going high, I fill the system. You will need an allen wrench and a small funnel to fill the system. Hope this helps you out.
#5
Old fart with a wrench
My 2000 doesn't have that plug, but I take the temperature sensor out and fill the radiator until coolant flows out that hole, re-install the sensor, then top off the radiator. Your engine should keep itself full from the reservoir. You just add coolant to the reservoir when it gets low. My 4.0 even tells me when it's low in the overhead VIC. As far as the fan relay is concerned, they changed it to 2 relays in the PDC. I believe you'll find that info on wjjeeps.com
Last edited by dave1123; 03-15-2016 at 03:47 PM.
#6
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Join Date: Jan 2011
Location: Boston, MA
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Year: 2003
Model: Grand Cherokee
Engine: 4.0 I6
Hope that helps,
Nick
#8
Old fart with a wrench
You see? I TOLD you they changed the circuitry! Don't mind me, I'm just a grumpy old man!
#9
My daughters 2004 Grand Cherokee has been over heating randomly when idling. The temperature sending unit and thermostat have been replaced. Still no solution. I read on CF about others with similar problems. I also read on here about the fan control relay possibly being bad and started into that task. Removed the headlight, cut the hole and walla!! NOTHING!! The holes are there where the controller should mount but nothing is in the area. (see photo) I have looked around under and over the whole area and can't find it. It is not another style located in the fuse compartment under the hood. Is there another area where I can look? Any help would be appreciated. Ron
Turns out the two relays for the fan is located in the fuse box behind the battery!
$10 part (each) and easy fix.
#10
Trying to locate the 2 speed relays for my 04 Laredo without success, I decided to check to see if the fan worked by jumping the connection at the plug and the fan kicked on. Going back to test the relays I decided to flip the AC on again because the fan worked for a short period yesterday. Sure enough the fan kicked on again.
Trying to figure out the connection, I could only conclude that the AC drew amperage and may fused a bad connection within the fuse panel.
I tightened all connections to the battery lead and started the motor. At 210 the fan kicked on!!!
3 more trial starts and letting the motor run for 5 minutes the fan stayed on as it should.
Hope anyone with similar issues can be helped with this.
Last edited by Gary Somers; 03-28-2020 at 02:19 PM. Reason: added photo
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BlueRidgeMark (03-28-2020)
#11
Old fart with a wrench
My God, Man! Take an airhose to that PDC and put the cover on it! Otherwise, later on, you'll be fighting corrosion and loose connections the likes of which you never seen! Oh, wait....I see the cover, but it looks quite dirty just the same.
Incidentally, a good thing to do with the relay under the headlight is bed it with the same compound they use under computer chips for good heat dissipation. It gets really hot from rapid cycling during low speed operation and it's carrying 30 amps. Great engineering using a 2-wire fan and a pulse modulated relay! Idiots! Your 2004 uses 2 relays and a 3-wire fan.
Incidentally, a good thing to do with the relay under the headlight is bed it with the same compound they use under computer chips for good heat dissipation. It gets really hot from rapid cycling during low speed operation and it's carrying 30 amps. Great engineering using a 2-wire fan and a pulse modulated relay! Idiots! Your 2004 uses 2 relays and a 3-wire fan.
Last edited by dave1123; 03-28-2020 at 08:39 PM.
#12
Can’t find cooling fan relay
I have a 2009 Jeep Grand Cherokee Laredo and I can’t find the relay that’s supposed to be under the headlight on passenger side. Any help would be great
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