Jeep Grand Cherokee – Overheating Problems
October 16, 2010 10:07 am DIY, Jeep
Access for the fan control module can be gained from behind the headlight.
© DenLorsTools.com Summary: This auto repair blog covers overheating problems with Jeep Grand Cherokees ranging from 1999 to 2004. The cooling fan module location is shown. The cooling fan module is a common problem that can cause the radiator cooling fan not to work. Time saving suggestion to allow much easier access to the cooling fan control module for replacement. Questions and answers for this and other overheating issues covered in comment section.
Jeep Grand Cherokees that overheat could have one of several problems. Coolant level is obviously the first thing to check. Low coolant caused from a leak can cause overheating and possible engine damage. A thermostat not opening could also cause overheating even if there’s no leak. Caution DO NOT open the radiator cap on any hot cooling system. With that being said, one very common problem is the radiator’s cooling fan not working. Jeep Grand Cherokees that have a factory tow package will have a mechanical fan attached to the water-pump in addition to the electric fan located closer to the radiator underneath the plastic shroud. Jeeps that have both fans, may not show signs of overheating unless being operated in extreme conditions. Conditions like pulling heavy loads or being driven hard in mid summer heat; Jeeps that do not have the benefit of the extra cooling fan will show signs of overheating much quicker if the fan motor stops working for any reason. The electric cooling fan is designed to come on when the vehicle reaches operating temperature or when the A/C is turned on. With the AC selected, the computer will command the fan to come on. It’s best to check the two wire harness that is attached to the passenger side of the fan shroud for power and ground. If using a power probe tester, the harness can be unplugged and power and ground supplied to check fan operation. If the fan works but there is no power being supplied normally, it’s a good possibility that the cooling fan control module has stopped working (open circuit).
An access hole has been made to make changing the module easy.
The book time for changing the coolant fan control module is 1.5 hours. It usually requires removing the entire plastic bumper fascia which is located behind the outer bumper cover. One and a half hours isn’t enough! That’s why most technicians will make an access hole to get to the module, The headlight assembly is easily removed after removing one long bolt. After that is removed, the headlight is pry-ed carefully with a trim stick or screwdriver. Caution should be taken when making the access hole, because a vacuum canister is located a bit closer to the front of the bumper! The vacuum canister is also made of plastic so it can be damaged when the access hole is being made if cutting in the wrong location.
Mopar fan module number is 04707286AI (Chrysler/Jeep)
By using the tips laid out in this auto repair article, DIY’ers may be able to pinpoint their Jeep Grand Cherokees overheating problems. Questions and answers below in the comment section.
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dennisb - Auto Tool Sales :
Date: May 12, 2015 @ 5:04 pm
Low power steering can allow air into the system. If your Jeep has the hydraulic fan clutch that uses power steering from the pump and not just a regular hydraulic fan clutch, maybe there’s some air in the system. Usually the PS pump will whine indicating there’s air in the system. It’s important to know that just because the fan clutch looks like it’s going slow at times, there may be nothing wrong. If there’s an over heat condition and the fan clutch isn’t pulling enough air through the radiator then there could be a problem. Good Luck.
Elvin :
Date: June 22, 2015 @ 11:37 pm
Hi there I have a 04 Jeep Grand Cherokee. The radiator exploded twice while on idle had new radiator installed and the thermostat, water pump was replaced long before overheating problems. The mechanic scanned the system and operated the fan through scanner tool. There’s no module under the headlight on my Jeep, only relays under hood. The high and low relays were replaced with Oem’s. Anyway the old ones were still good and we could not find any problem. Today while driving in 95 degree outside temperature with the A/C on, the engine’s temp went up to 225 and switched off the A/C. When the engine temp went back 210, the AC restarted. Opened the hood and saw the fan was running on low speed. This was the very first time the engine overheating caused the A/C to turn off. Too hot! Any help would be appreciated, I’m frustrated. Thank you.
dennisb - Auto Tool Sales :
Date: June 23, 2015 @ 7:13 am
I’d check with the scanner to make sure the vehicle’s computer is seeing the same temp as you’re seeing on the dash gauge. There’s two different sensors. I’d also make sure there’s no air in the cooling system, the engine oil is clean and full and transmission fluid is full also. You can get some heat transfer if the engine or transmission is running hotter than it should be. Also that there’s no obstructions blocking airflow for the radiator and condenser. Sometimes when the fan is spinning slower than expected it could be failing. If you lightly tap on the fan motor and the speed picks up, I would plan on replacing it. Good Luck.
Elvin :
Date: June 25, 2015 @ 6:32 pm
Thank You Dennis, I had the fan replaced new OEM drove all day with the A/C on and no problem I can actually hear how loud it is on high speed huge difference thanks again for your help.
dennisb - Auto Tool Sales :
Date: June 26, 2015 @ 7:45 am
Ah the old slow fan issue! Sometimes hard to diagnose because it appears to be operating normally. Elvin, glad you have this resolved.
Debbie :
Date: November 23, 2015 @ 4:10 pm
I have a 2002 jeep grand Cherokee Laredo 4.0. overheating, replaced thermostat and gasket, temp gauge sensor. jumped out fan, fan would run but fab will not operate with A/C defrost. replace control module for fan, operated 3 times then quit. we have no blown fuses. please help.
dennisb - Auto Tool Sales :
Date: November 23, 2015 @ 4:53 pm
The condenser fan may not come on with defrost unless the high side pressure reading gets high enough. If it’s not overheating and the condenser fan comes on when the high side ac pressure readings reach around 350-400 psi, it is operating normally.
Mara :
Date: November 29, 2015 @ 4:26 pm
My radiator fan is super fast…. why and what to do? It was overheating and changed the water pump which it needed it and the thermostat. I bled the system and now the jeep is not overheating but the fan is as fast as a helicopter
dennisb - Auto Tool Sales :
Date: November 30, 2015 @ 7:46 am
If it never goes to a slower speed or shuts off there could be a stuck relay. It will take some testing and a scan tool. Good Luck.
Mara :
Date: December 5, 2015 @ 10:52 am
Im still puzzled, last night I was out there replacing radiator and fan. So far I changed the water pump, thermostat, fan and radiator.Flushed the radiator fluid and pour new one. I started the 4.7 GC and it seems good. I took it for a test drive and maybe 5 minutes after driving it temp rised just below the 260 mark. Im thinking flushing the power streering fluid and see what happeends since the fan is hydraulic.
dennisb - Auto Tool Sales :
Date: December 5, 2015 @ 1:21 pm
I’d check engine oil for level and condition. Check for air in cooling system etc. Fan would not be the issue unless it only overheats at a stop. A blown head gasket could be putting exhaust into the cooling system. This can be tested with a carbon test which will let you know if exhaust is in the cooling system or not. Good Luck.
Jennifer :
Date: February 21, 2016 @ 10:26 pm
I am getting sick of having to change the fan relay about every 6 months. Any ideas on how to remedy this or a decent replacement part since jeep seemed to drop the ball on the 2003 wj with the inline 6 as is is a piece of garbage part…
dennisb - Auto Tool Sales :
Date: February 24, 2016 @ 4:17 pm
I’d replace the fan motor too, since it’s most likely pulling to many amps causing the fan relay module to fail prematurely. Good Luck.
michael :
Date: February 29, 2016 @ 5:13 pm
I have a 3.7 06 jeep cherokee. My jeep is over heating after driving for about ten minutes. I replace the thermostat and water pump. Still overheating. Also heat doesn’t work. Please help before I put more money into it. When it over heats I turn it off and it says transmission over temp. Does not start until about 30min later
dennisb - Auto Tool Sales :
Date: March 1, 2016 @ 8:57 am
I recommend towing to a shop to have someone in person check it. Could be a blown head gasket or something simple like a radiator plugged. Good Luck.
Beverly Youngblood :
Date: March 13, 2016 @ 6:55 pm
I have a 2003 JGC Laredo 4.0 straight 6. Car seems to over heat at idle and fan WILL NOT come on, will not even come on with AC ON. I don’t know what to do. I’ve replaced the fan relay and the fan motor. I do not have a towing package on this so just have the 1 fan. Is there something not allowing power to get to the fan telling it to come on? I am desperate. My one and only car.
dennisb - Auto Tool Sales :
Date: March 14, 2016 @ 9:01 am
I would command on with scan tool and test with a DVOM to see where power (or ground) loss is. Knowledge of electrical circuits and how to use test equipment will be needed. Good Luck.
Amy :
Date: August 26, 2016 @ 9:40 pm
2004 Jeep Grand Cherokee laredo 4.0L with in line 6. Started over heating while stuck in traffic. Changed the thermostat and gasket. Still over heating when in traffic and idle. Went to change the relay but it’s been bypassed already. Changed out the whole fan set up. New radiator cap. It still over heats. I’m at my wits end. What else can it be?
dennisb - Auto Tool Sales :
Date: August 29, 2016 @ 7:37 am
I would suspect the radiator itself. Good Luck.
dallas :
Date: September 1, 2016 @ 9:33 am
I have a 2000 Jeep Sport 4.0 that heats to 210 and at idle it will go 215. Then the fan comes on. I’ve replaced the timing chains and gears , replaced water pump. Replaced thermostat, filled with new fluids. It still overheats, so whats a country boy to look for now, help help
dallas
dennisb - Auto Tool Sales :
Date: September 1, 2016 @ 9:56 am
I’d double check temp with scan tool looking at data screen. That uses different temp sending unit than the sensor that triggers fan. Could be the sensor is a little off or maybe the radiator not quite up to par. Good Luck.
bernard :
Date: June 18, 2017 @ 8:32 am
I have a 2005 grand jeep cherokee, its stops when temperature reaches about 85 degrees C (185 F). I have checked coolant and replaced it what else can I do?
dennisb - Auto Tool Sales :
Date: June 18, 2017 @ 9:35 am
If the engine stops when the temperature reaches only 185 degrees F, or if the temperature only reaches 185 F, I’d question if that temp is accurate. Have someone check with a scan tool that can view data, which will use a different sensor to verify. Good Luck.
sissy :
Date: August 9, 2017 @ 7:15 pm
I have a 2000 jeep grand cherokee, I replaced radiator because somehow it blew up last year. Temp has been good all year. Went to take kids on vacation it was hot out and traffic going slow noticed truck getting hot pulled over a man came over took off radiator cap everything all over . Refilled with antifreeze, Went 3 blocks and boom hose busted. Towed to mechanic said the harness was melted so fan was not kicking on was wondering if it could have melted when hot fluid went all over.Changed hose and all fluids and he said he got a spark so the fan worked. 3 days later coming home temperature going up again in traffic, pulled over and waited until evening to continue home. Got home no problem i guess because I was getting a lot of air. My son checked with his diagnostic tool and it said it was the temperature sensor. I know we replaced it last year. My question is do you think it is the electrical harness module that comes apart then connects back, that they said was melted but then continued to work or would it be the temperature sensor like the diagnostic tool said. thanks
dennisb - Auto Tool Sales :
Date: August 10, 2017 @ 7:13 am
Hot coolant won’t melt wiring. There’s a temp sensor and a sending unit. One is for telling the computer the temp so it can command fan on. And the other one tells the dash gauge what to display. Some actual testing has to occur to determine what the problem is. The most common issue is the module, but in my experience they either work or not and are not intermittent. I’d be checking for a blown head gasket at this point since it has been overheated so many times. Good Luck.