Engine Cooling problem
1998 Dodge Caravan 6 cyl Front Wheel Drive Automatic 102000 miles
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Hi, I have a 1998 Caravan and the engine cooling fans wont go on. Ive replaced the relay and the temp sensor. I have checked the temp sensor with a ohm meter to make sure the resistance changes when the engine warms up, and it does. Th sensor is working fine. When I pull the connector off the temp sensor the fans go on so I know the fans and fuses are fine. For some reason it seems the computer module isnt sending a signal to the relay to turn the fan on. I get the trouble codes P1491(radiator fan relay circuit fault) and P0118(engine coolant temp circuit high input). I am also having a problem with the air conditioning not working. When I do the self diagnostic test on the A/C the results are that it fails the cool-down test.

Does you have any ideas why the computer module isnt sending a signal to the relay? Could the A/C problem be causing the cooling fans not to come on? Could there be a problem with the computer module?

the 1491 is usually caused by a bad fan relay and or a blown fuse feed to the relay. if ok possible bad computer

Im not getting the 1491 code anymore that went away when I replaced the relay. But I still get code P0118(engine coolant temp circuit high input) and the fans still dont go on. The sensor seems to be working because I tested it in a pot off boiling water and measured the resistance while it was still on the car. For some reason the PMC wont tell the fans to go on.

now we need to install a scan tool and watch the temp at the computer