Question about 1999 Jeep Grand Cherokee

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Overheating engin when at idel, fan not working

99 jeep cherokee lerado, stuck in traffic it overheats, the fan deesn't ever turn on, electric cooling fan controlled by the pcm. 4.0L 6 cylinder. The top radiator hose gets hot so i feel that the flow is good in the radiator.

About 1500 miles ago the dealer replaced the TPS(Throttle Position Sensor) from diognostis code check engine light. 500 miles ago dealer replaced the speed sensor on the crank case. Now this sounds like another relay, sensor switch etc. problem.

I know i have to get the fan thing figured out so what do you think on that, but do you think the PCM(Power Control Module could be the result of all these problems happening since the last oil change. Doesn't seam to be too coincidental.

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  • Anonymous Nov 25, 2008

    I also have a 1999 jeep grand cherokee 4.0 liter v6 an dit also overheats due to the radiator fan not working. from talking to mechanics i found that this is a comon problem for this vehicle alog with some other things. I replaced the fan myself not even a year ago and just now it stopped working on me again. i guess i'l just replace it again.

  • s51093san Dec 14, 2008

    I purchased my 1999 Jeep Grand Cherokee Laredo from a dealer in 2002 (38,000 miles) I owned my truck about 1 month when my water pump stopped working, the dealer replaced it and about 30 days later I needed another water pump, I advised the dealer to replace it with a new not rebuilt, they did.... not more than one year later my radiator blew up no warning nothing just cracked right in half.... replaced the radiator and 8 months later needed a new waterpump... fixed that and 13 months later the fan froze up... replaced that and one year later the radiator blew again... here I am about a year later and again without warning the damn thing overheated again while sitting at a light for not more than 3 minutes.... the radiator again is cracked (yes always new parts never rebuilts).... does anyone have any insight into how to fix this problem... Jeep claims they know nothing of it but reading all of the posts here I believe they are very aware and are just trying to **** me dry.... no I will never buy a jeep again but I need to keep this one until I can afford to buy a new car....

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Does both the hoses get hot bottom and top? this will tell you if theres flow through the radiator. If you have a voltage tester test the wires on the fan connecter check there is current going to the fan if so replace the fan its a common problem as previously stated. 
if there is no power to the fan when the vehicle should be turning it on i.e. its hot enough check the fan relay under the hood.

Posted on Nov 27, 2008

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