Overheating issue


Asked by May 21, 2013 at 01:57 PM about the 2003 Jeep Grand Cherokee Laredo 4WD

Question type: Maintenance & Repair

Last summer, my jeep overheated. A friend of mine said it was probably the sensor, since the fan would work when he tested it, so he ghetto rigged the fan to a fuse inside the car. The connection was shotty at best and kept coming out. I didn't have issues during the winter as it's cool around here. Now that it is getting warm, the Jeep started overheating again. I had someone else look at it and determine at some point that the fan motor burned out. It was replaced, but still had the wire rigged to a fuse to turn on with the ignition. The connection still sucked. So I decided to replace the sensor. I paid a shop to replace the sensor. Now the fan doesn't come on at all. After doing some driving, the water boils. Every time. Sometimes it will get so hot it will boil over. I have to wait for it to cool off and put more water in. I was going to buy the relay switch, but I want to know before I do if this is the issue or if I'm overlooking something else. I don't want to keep just replacing parts and have it continue to not work. Thank you for your help.

22 Answers


Did you try replacing your thermostat?

5 out of 5 people think this is helpful.

No, I have not. But it does register the temp on my gauges. Would the thermostat cause the fan not to come on when it's supposed to?

6 out of 6 people think this is helpful.

The engine is not supposed to over heat at all. Having the fan running does not cure the problem. The only time the fan should energize is when you're stuck in stop and go traffic or the Jeep is towing heavy loads up hills. Sometimes they come on with the air conditioning.

1 out of 1 people think this is helpful.

My jeep doesn't overheat just driving. If I'm doing freeway driving or not much stop and go it's fine. It's only when I'm doing a lot of in town, stop and go driving (ie: lots of traffick, Idling, things like that) and on warm days. I know that the fan is not coming on when it is supposed to and that is the issue with the overheating. When the fan was hooked up to the fuse box and it was coming on all the time, it was staying below temperature. It does not turn on when I idle (even if the engine is getting hot). I'm trying to find the issue with why the fan would not be turning on.

13 out of 13 people think this is helpful.

Anyone have any help for me????

1 out of 1 people think this is helpful.

No answer yet but i have a similar issue. When my Ac is on the engine begins to overheat. When i turn the AC off, it cools back down. The pwm fan seems to be spinning slowly and i wanted to test it. What wires to i jumper to test that the fan is good?

9 out of 9 people think this is helpful.

There's a fan relay located under the right head light. You either remove the bumper or cut into the headlight plastic mounting to get to it. I cut into the mounting, bend it out, replace the relay and tape it back with duck tape. The headlight assembly slide over it. No one will see.

8 out of 8 people think this is helpful.

I'm having a similar problem 2003 jeep cherokee over heating change relay and sensor plus the themorstat and put in a new radiator and when I start to drive within 10 minutes it start to overheat and start to boil I even try to take out the air pockets any help please

12 out of 12 people think this is helpful.


4 out of 4 people think this is helpful.

I have the same issue on my 05 Cherokee and was told my water pump was leaking. Funny thing is I just replaced the water pump 1 year ago! Fan turns on sometimes! I don't have a clue why.


I have 2004 Specisl Edition stright six with the same problem I have replaced the fan,thermostat and radiator. No relay switch can be found or the sensor for the fan. Just put another fan in, it's barely moving and still running hot. An appointment has been made with Chrysler, figure its their product they should have the answer. Will post results after repair.

1 out of 1 people think this is helpful.

I have a 2004 Jeep Grand Cherokee and every time I sit with my car in park for a while it begins to overheat and I have to wait till it cools down. So I don't know what it is or why it's happening any thoughts?

11 out of 11 people think this is helpful.

Same problem as above combined with my steering making the strangest groaning sounds at the same time as it starts to heat up while say waiting at a drive through plus the fan at the front goes wild. I also am hearing a significant amount of water sloshing near the firewall on the passenger side whenever I 1st start movi g forward. Then after I stop, I can literally HEAR the water boiling.

4 out of 4 people think this is helpful.

I have a 2008 grand Cherokee, I was having the same problem, my car would get super hot just sitting still in traffic or idling. I replaced my radiator cap which didn't work, I took it to 2 shops and no one could figure it out. Finally my uncle looked at it, we flushed my engine and the radiator and replaced the thermostat and it hasn't over heated since! The thermostat wasn't opening when my car started getting too hot! Hopefully this helps

2 out of 2 people think this is helpful.

Hi all I have a solution for some of you. I own a 2002 cheeokee. I replaced the thermostat, radiator and the cooling fan in the event the fan wasn't coming on high speed. I have an electric fan. The 2003 and higher have both an electric fan and a clutch fan. I went to a football game last week tailgating and left it running for 30 mins with ac on. I just happened to notice the temp gauge. The antifreeze was boiling. How the hell can my jeep overheat with a new electric fan, new water pump, new thermostat and new radiator. I replaced all of them 3 months ago as preventative maintenance. Still overheats at a standstill even though the electric fan is working on low and high speeds. Well I found out in 2003 they put 2 fans in. One electric for the radiator and a mechanical clutch fan to cool the engine. So, I bought a mechanical clutch on eBay for $32 and a plastic mechanical fan for $23 on eBay. Installed them onto the front of engine pully (just screws on with your hand) and now I have 2 cooling fans and no more overheat issues :)

4 out of 4 people think this is helpful.

And ps my fan relay is brand new too


MBella2000, I never knew about the fan that mounts on the pully. Is it literally just like a plastic fan blade that mounts on and spins as long as the engine (pullys spinning )is running? I definitely need to put one on my 2002 grand cherokee seeing how I live in hot ass south west florida lol. I just bought this jeep like 3 weeks ago and didn't know shit about jeeps. It has a new thermostat, water pump, I just put a fan relay in today, and it still over heated, I am going to get a radiator flush next, but regardless I want to put that second fan in because it can't do nothing bad to it but make it run cooler so I definitely want to do it. What do they call it exactly so I can look it up to buy one, or if u can post the link for it I would appreciate it so much. Thank you and I hope to get this issue solved seeing how I'm not rolling in money right now, u kno? Lol

1 out of 1 people think this is helpful.

I own a 2002 grand cherokee, I am reading the answer from MBella2000, do you have a picture of the Fan you bought on E- Bay? Can you share it with us, please?

1 out of 1 people think this is helpful.

I have question about my 2004 Jeep Wrangler Rubicon. When driving in town the AC/Heater blows air just fine. After 30 minutes of highway driving it quits blowing. If I stop and kill the motor it will blow for 30 minutes and shut off. The other evening my temp gauge read hotter then normal, but immediately cooled down once I reduced speed below 40 mph. I checked fluids and all were normal. I have driven it the last 2 weeks and no sign of overheating, but still has an issue with AC/Heater.

The guy that mentioned the relay hidden behind the passenger side headlight mounted to the fender has the answer for many of you. My problem is a thermostat that goes up and down, I believe a short ground somewhere. And the car shocks me getting in and out. Anyone has this problem?

Yes except the piece that was burnt up on our 2001 Jeep Grand Cherokee was the connector the fan relay switch hooks into we saw it was burnt causing a bad connection to the fan causing it not to cut on and overheat while idling . Went to junkyard got need connector cut old one out retape the wires and our fan works now here's a picture

FYI fan relay switch is under passenger headlight under the plastic header panel check the connection the fan relay switch and what it hooks into if any looks corroded or burnt that is most likely the reason why your fan won't cut on causing the car to overheat. We smelled a burning smell going down the road and right after the fan stopped working and car overheated

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