1999 Jeep Cherokee Trouble code p1491

1999 JEEP CHEROKEE
180,000 MILES • 6 CYL • 4WD • AUTOMATIC
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BLUEKRAWLER
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I was heading up to the trail one weekend when my AC stoped blowing cold air and i recieved a check engine light. Shortly after my engine started to overheat. While letting my engine cool on the side of the road, we noticed that my auxillary cooling fan was not on. We hard wired the fan with an inline switch and 25 amp fuse to temporarily fix the problem, which it did. Upon arriving home i reconnected the original wire harness and replaced the Radiator Fan Control Relay. Fan and AC still failed to operate with warm engine and AC on max. Manual suggested replacing temperture sending unit, Relay, Fuse, and even AC clutch Relay. Replaced all. Still no Auxillary fan or AC. Where do i go from here? Thanks in advance for the help. -Malcolm
Jan 26, 2010 at 12:41 PM
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CYBER TECH
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Where was the relay located that you replaced. Most people can't find it so I'm wondering if you changed the right relay. Let me know.
Jan 26, 2010 at 5:49 PM
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BLUEKRAWLER
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Relay was located in engine compartment, passenger side in box marked "For Access to Fuses and Relays Pull Tab". Multiple big block fuses and relays. Relays were labeled accordingly under box lid. Replaced Cooling Fan and A/C Clutch Relay's.
Are you thinking my Relay is located behind the driverside headlight? I thought that was the answer to my problems after much research online. I immediatley called the local jeep dealship to order the relay. They informed me that they do not sell nor do their computer's indicate a relay in that position. I double checked my jeep and negative on relay located behind headlight.
Jan 29, 2010 at 9:12 PM
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BLUEKRAWLER
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Shop told me they traced my wires upto the PCM. PCM was recieving but was not transmitting that the cooling fan needed to be activated. As of wires C1 and C2. $50 for diagnoses. OK. Ordered PCM from J & W Jeep Recyclers $250. Installed. Still reads codes as follows. P1491-Radiator Fan Control Relay Circuit. P0443-Evaporative Emmision System Purge Control Valve Circuit. Bear in mind my A/C does not work. It will blow air but not refrigerated air. So im stuck. Cant sign off expired registration ticket without smog. Cant pass smog with a check engine light on. Cant clear check engine light with problem unsolved. Cant afford more shop bills (got layed-off after thanksgiving) When it rains, it pours right......
Jan 29, 2010 at 10:18 PM
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CYBER TECH
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The most common issue for this is a blown fuse. Be sure and check fuse #5 which is a 40 amp fuse. This is in the underhood fuse box.
Jan 30, 2010 at 12:40 PM
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BLUEKRAWLER
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Fuses and relays were the first to be checked and replaced. Triple checked again the other day and none are blown.
Feb 8, 2010 at 11:52 AM
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JACKCOLE3
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Engine Cooling problem
2001 Jeep Cherokee 6 cyl Four Wheel Drive Automatic

Replaced relay fan works when hot wired but will not come on on its own.
Dec 29, 2016 at 5:50 PM (Merged)
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BLUELIGHTNIN6
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test engine coolant temp. (ECT) sensor
Dec 29, 2016 at 5:50 PM (Merged)
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BLUEKRAWLER
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Im going through the same issue with my '99 cherokee as well. I gave up and brought it to the shop in hope that they can solve my headach. I'll let you know the out come if your interested. -Malcolm
Dec 29, 2016 at 5:50 PM (Merged)
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[email protected]
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Too bad you're bringing it into the shop. The cooling fan relay is a cheap basic fix. Just takes a little time to take the bumper cover off to get at it, but other than that it's 2 screws, $30 part. Could have walked you through it I've replaced mine twice.

The cooling fan relay from 99-2001 go bad all the time. You need to replace that for sure. The fan will not turn on until the engine is hot enough for the relay to kick in and turn the cooling fan on
Dec 29, 2016 at 5:50 PM (Merged)
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BLUEKRAWLER
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There is no Relay behind the driver side headlight in a 1999 Jeep Cherokee Sport. I herd that from a shop and thought it was the answer to my problems. Then i got around to calling for a price. The local jeep dealership dosnt carry nor do there computers indicate a relay in that position. Tough for me. More trouble shooting....
Dec 29, 2016 at 5:51 PM (Merged)
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[email protected]
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I was talking about 1999 GRAND Cherokee
Dec 29, 2016 at 5:51 PM (Merged)