Cooling Fan Motor Trouble.. Help....

BArtkowsky

Registered User
Ok, I have a 92 SC. I had repalced the thermostat with a cooler one a while ago unaware that i had to reset the EEC. Well My Cooling fan would rarely come on at one point as far as i know and the temp guage was at the M in Norm. Now the fan doesnt come on unless i unplug the ECT sensor. Well I just replaced the sensor and it is not the sensor. I unplugged the connector for the ECT and the fan came on i then uplugged the fan connector by the fuse block under the hood behind the battery. Now with the ECT unplugged and the fan running, the fan shut off when i unplugged the connector by the fuse block. Fan seems to work good (when the ECT is unplugged) but when i shut the car off the fan makes some slight "whh---hhearing) noises when it is slowing to a stop. Is this normal? I ordered a new fan motor from advance where i work for 70 some dollars with my discount to see if that could be the problem. Should be here by friday. Does anyone know if that could be the problem. I know someone before had mentioned about resistors in the motor going bad. Umm now could the fusible link be bad if the fan ran while the ECT was unplugged? and the fan shut off when i unplugged the connector for the fan near the fuse block (the one that people say tends to melt when the fan goes bad) Could it still be the fusible link? Im thinking either the fan motor is on its way out or the IRCM, but with the slight "Whhh---irring" Noise im thinkin it could be th fan motor. Anyone with experience in this let me know, Thanks alot, Brandon
 
Not sure about the other problem but I beleive the only way to make the fan come on sooner is with a chip.Even though you changed the t-stat to a lower temp range you're computer will still only turn on you're fan at the preset temp that is controlled by the chip.


Jay
 
Sounds like the low speed windings in the fan are blown, thus you don't notice it come on until it gets really hot, which is the point the EEC turns on the high speed windings.

The new motor should clear that up.
 
The fan doesnt come on at all unless I unplug the ECT but with the ect unplugged if i unplug the connector next to the fuse panel under the hood then the fan shuts off, could that stil be the low speed windings, it does bog the rpms way down when i unplug the ect and the fan comes on..
 
Low Speed Fan

If you cut your #14 wire off your IRCM module your low speed fan should run all the time. (Leave enough wire so you can crimp on a connector at a later date) This will tell you if your low speed windings are gone. I ran it this way for a year or 2 on my 93sc and it helped keep the car temp a little cooler, though it tends to wear out your fan a little sooner.

JT
 
OK heres the thing... i am assuming my IRCM is bad. I have replaced the ECT sensor. I have just replaced the fan motor. I have checked voltage to the fan connector(with ect unplugged it reads normal volts with it plugged in it reads zero). I have just cut the #14 wire after replacing the fan motor and the low speed now runs all the time. I have cut a chunk of insulation off of each end of fusible link B (blue to yellow wire coming off the starter solenoid by the fuse panel under the hood thats read fusible link) and checked the continuity with my craftsman voltmeter anf there was continuity between each side of the fusible link. One question though, What the f*** is the the sensor mounted in the Heater hose near the throttle linkage and the pass side front shock actuator, is this another temp sensor??? With the # 14 wire cut and running the low speed fan I unplugged th ECT and it seemed to have kicked in the High speed fan( whwn the low speed was already running). Am I correct on that? Before i had cut the # 14 wire form the IRCM I had unplugged the ECT and it had bogged the rpms way down (possible due to eccesive current drawsince the low speed was not kicked in first?) This car is such a WH*RE but its my baby and i'll never sell CAUSE I LOVE THE THING although it tends to piss me off alot, LOL. I should name it the Mystery Machine even though its not a van. Going on almost 6 yrs as a SC owner(same vehicle) Anyways after checking all that, does it man that is the IRCM? Lemmie know what younz think... thanks, Brandon
 
First off, the ECT sensor that you keep unplugging is actually used for alot of things than just "controlling" the fan which it doesn't as the EEC does that. The EEC will detect a fail mode when the ECT doesn't send a signal so it will turn on the high speed fan to protect the motor from overheating since it doesn't have a way to measure temperature.

The EEC will also put the car into a limp mode, which essentially just enough fuel and timing to run the motor so you can get home. Do you have autoclimate control? If so, that explains the other temperature sensor that you see near the throttle body.

Personally, instead of cutting a wire to test if low speed worked, I would have unplugged the fan and ran power directly to the fan. If you don't know which wire is which, I'm sure someone around here could have told you the colours of the wires. If the low speed ran, then I would suspect the IRCM module and looked at getting ahold of another for testing to confirm.

In the state you have it now, IF the car gets hot enough and the EEC activates the high speed mode, while the low speed is running you will cook something and get alot of current draw because both speed windings will be fighting each other. Also, the reason for the huge current draw when the high speed kicks in, is normally the low speed will have the fan running, then the EEC kicks off the low speed windings and turns on the high speed which accelerates the fan. The high speed windings where not designed to start the fan turning.

Hope that explains things for you.
 
Fan

So just to verify - after you put in the new fan motor, your low speed fan didn't come on even after driving it for awhile? It doesn't come on until you get to a certain temp, I believe around 220.

If your positive the low speed fan isn't coming on at all then probably your IRCM needs replacing.

You can drive around for awhile with the low speed fan on (#14 wire cut) until you find another IRCM. It's safer then driving around relying on the high speed fan to kick in which causes a huge current draw, not to mention your engines going to be running fairly hot all the time. My Temp gauge was always around N when having the low speed fan on all the time and it never got hot enough to trip the high speed fan. Ran for 2 years without any problems. But if you do have another problem - eg - rad or waterpump and your temp starts to rise up close to the M in NORM you could run into the problem described above where both fans come on and you'll end up smoking some wires.

Recently connected my #14 wire though, as I have a CHIP now that's programmed to bring the fans on a little sooner then was programmed for stock..
 
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So just to verify - after you put in the new fan motor, your low speed fan didn't come on even after driving it for awhile? It doesn't come on until you get to a certain temp, I believe around 190.

If your positive the low speed fan isn't coming on at all then probably your IRCM needs replacing.

You can drive around for awhile with the low speed fan on (#14 wire cut) until you find another IRCM. My Temp gauge was always around N when having the low speed fan on all the time and it never got hot enough to trip the high speed fan on. Ran for 2 years without any problems.

Recently connected my #14 wire though, as I have a CHIP now that's programmed to bring both low and high speed fans on a little sooner then was programmed for stock..

Try 220 for the temp in a default setup for the low speed, with the high speed coming on at 228.
 
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