radiator fan relay failure issues-overheating blowing relay

Asked by Jul 02, 2013 at 09:00 PM about the Jeep Cherokee

Question type: Maintenance & Repair

I am tired of replacing radiator fan relays on my 2002 grand cherokee.I have researched and determined that the best fix is to is to install towing package fan system which is an engine driven manual hydraulic clutch system.My concern is will I still get engine code P 1491(Radiator Fan Control Relay circuit)?If so how can i nullify it?

5 Answers


Woah, slow down there, cowboy- wouldn't the best fix be to find out why your relays are blowin' up? (simple, cheap?)

6 of 6 people found this helpful.

excessive resistance in the fan motor.....does it every time...

7 of 7 people found this helpful.

My 02 Grand Cherokee won't currently start. The error code I'm getting is P1491 , plus some O2 sensor codes that I've had for the past couple of years. I just replaced my serpentine belt about 100 miles ago because the idler pulley and the tensioner pulley were stuck and the belt ended up breaking. I replaced both pulleys. Will the P1491 prevent the Jeep from starting?

3 of 3 people found this helpful.

Does it crank no start. Or just no crank? Are you using the gray headed key? as this is a special programed key. there is a 50 anp fuse in underhood fuse box. Is it missing or blown? Did you deplace the relay that is under pass side headlamp?

1 of 1 people found this helpful.

I've been driving with P1491 for a couple of months and haven't had any overheating, but it is winter in Chicago. P1491 means the powertrain control module (PCM) can't communicate with the fan relay circuit. The service manual says to check for an open or a ground between the two. My guess it could also be that the relay is fried which can happen if the radiator fan pulls too much current (>40amps) causing the fan relay to overheat and fail. If you replace the relay and it fails again chances are the fan itself needs to be replaced too, and a new fan may also be bad so check its resistance! thejeepdoctor - too much resistance in the fan won't cause the fan relay to fail. It's too little resistance that causes the failure.

1 of 1 people found this helpful.

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