The system itself is rather complex. You have three fans, 1 pusher and 2 pullers. There are primary and secondary cooling fan switches, both in the radiator. There are somewhere in the neighborhood of 5 relays, and equally as many fuses. One of the fuses labeled clamp 15a is in the fuse block under the knee bolster below the steering wheel, fuses 40, 42, 50, and 52 are in the triangular ecm housing under the hood, and the lid provides no legend as to who is who. I would check for any blown fuses with a test light to ground, in this underhood fuse/relay center. It is quite possible that you will find a blown fuse, one of the green 30 amp ones. You also have auxiliary water pumps that are powered with the same circuits. It is quite common for one of these pumps to cause a problem. One is mounted on the RH frame rail, and one is mounted at the left(drivers) side of the radiator. Pull the electrical connections of these pumps, and check for corrosion on the terminals. Coolant usually leaks into the electrical connection and shorts the pump. If you want some schematics for the system reply to this post, there is about three pages, and like I say, they are complex.
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Wednesday, July 27th, 2011 AT 5:09 AM