I've got a 93 mustang LX with a 4 cylinder engine. My issue is the radiator fan will not come on. It will come on when the air conditioner is running. On the highway its not a problem, but sitting still it starts to overheat as the fan is not coming on. Have taken it to several auto repair shops with out any luck. Does anyone know what controls the fan when the air is off? Thanks,
The electric fan is controlled by the PCM (powertrain control module) and CCRM (constant control relay module). The fan activates when the engine temperature is 221 degrees F and off at 200 degrees F. When the A/C is on, the fan activates when vehicle speed has insufficient air flow; turning on at 43mph or below and off at 48mph.
One thing would be to verify the command signal from pin 51 of the PCM to pin 14 of the CCRM. The CCRM then outputs power to the fan on pins 1 or 2 (probably one for A/C mode and the other for non A/C mode). At any rate, either one of these modules could be suspect. The PCM may not be getting a valid input/inputs from sensors. If your planning on shotgunning parts, I would try the CCRM first. May want to consider buying one from a salvage yard. The CCRM is mounted on the RH front strut tower...Good Luck
-- Mike
93 CobraYour fan is controlled by a cooling fan temperature switch. It comes on ( closes) at 215 degrees. It is located on the lower intake manifold on the drivers side ( it points out to the fender) it has a yellow with red stripe wire to it. It actually sends a signal to fan control module that turns the fan on. When the A/C is on it sends a signal to that module to turn on the fan also. The fact that your A/C turns on the fan makes me believe the module is probably OK but that your switch sender unit is bad. I have the same problem with my 2.3 but my car never seems to get hot enough to turn it on, but I'm up here in the Geat White North ( although it is currently ablaze with yellow and red at the moment!) ;^) HTH StuK
Will that switch work on a electric fan conversion ??
Or where/how is a thermo switch added in this conversion ???
Well it "grounds" to the block when it hits that temp. I guess you could use it but I would have it complete the primary circuit of a relay and have the secondary carry the current of the fan, as the fan motor will draw a lot of juice that the switch probably won't handle for too long. StuK
a variable speed fan control @
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