Questions and Answers
Sundance Cooling Fan
Q. Vincent, My car is a 1994 Plymouth Sundance with a 2.5, non-turbo automatic with A/C and P/S. After replacing the head gasket, the radiator fan motor will not come on. The system was thoroughly bled. The entire cooling system has been replaced. The coolant temperature sensor reads between 725 and 790 ohms when hot.
The relay works and activates the fan motor when the sensor is disconnected. The relay works and activates the fan when the A/C is activated. Most interesting to me is that if I activate the fan via the A/C switch, it will remain on even after the A/C is switched back off. The fan will continue to cool and then shuts itself off at the appropriate time.
The fan just refuses to actuate of it's own accord. Now the best part, I hooked up a voltmeter to the primary of the fan relay and drove the car around, the fan relay receives no signal, the fan does not come on, BUT the car runs cool. Actually a few degrees cooler than it should.
The only thing left is the computer. I figure the resistance is too high somewhere in the circuit board of the engine control computer (or whatever they're calling it this year) that's why the fan won't activate on it's own, but will function normally after being momentarily activated by the A/C circuit. I would appreciate your expert opinion before I go buy a new computer.
Thank you,
FrankA. Okay, at the PCM connector Pin 9 (dark blue wire) you should have power with the key ON. Pin 31 (pink wire) of the PCM connector is the ground. Check for 12 volts at the PCM and the fan control relay. If you have it at the PCM and not the relay, you have a broken circuit. If you do, ground the pink wire at the fan control relay, the fan should come on. If it does, everything up to there is good.
Now, ground the pink wire at the PCM connector, the fan should come on. If not, broken wire. If it does, PCM is bad.
Additional Information provided courtesy of ALLDATA
