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[FIXED] 01 Jeep Gr. Cherokee 4.0L - No coolant fan operation
Hello I have a 2001 Jeep Grand Cherokee 4.0L With a code P1491 Fan circuit. Has new fan ass'y, relays, coolant temp sensor and a newly replaced reman pcm from another shop.. Testing done : At fuse box B+ at 30 on both low speed & high speed relays & KOEO B+ on 86. Can place B+ on 87 and fan will operate. All circuits have been voltage drop B+ & Ground even temp sensor wires. With connectors at PCM unhook ground voltage drop pin 2 & pin 21 which go's to 85 on both relays shows good. Can also ground these two one at a time and fan operates. Why does this P1491 kept coming back when engine starts with ac on. Also w/o ac on fan wont come on with engine temp or default fan operation from pcm when unhook. Thanks Charlie
Yes no bi-directional output to fan relays on pin 21 or 2 from reman PCM. After my testing I finally talk the shop owner into getting another reman PCM (that was hard because he just got the one I was testing with) The second reman fix the problem, so watch out on some of these reman computers on these Chrysler products, some may not have correct programming. Thanks for the replies...
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