Cooling Fan not coming on

supercoupe92FL

Registered User
Ok well I have been using a manual switch to turn on my fan for almost a year now and I am kind of getting tired of it.

My fan does not come on by itself even with the A/c turned on and cutting the #14 wire on the IRCM. The next thing I am going to try is replacing the coolant temperature switch. Is the switch and sensor the same thing? And where is/are they located. ALso is the fan relay in the IRCM? I read somewhere about taking the IRCM apart and checking for dirt buildup in there.

On a side note, with the manual switch setup, I am not sure if it is the high speed or low speed fan that is coming on when i turn it on. I've read having it come on high speed can burn out the motor. I have the wires plugged in to 2 holes that are parallel to each other. Is this powering the low speed or should I move them around?

Any insight would be appreciated, thanks!
 
well ill add my 2 cents.....first off i almost had the same exact problem....my fan wouldn't come at on at all....so i finally cut my 14 wire to have it come on all the time......reason im not happy though is becasue i replaced the ircm the coolant temp switch and i know the fan is good yet it still doesn't work.....and it seems to me that this is a real problem with this car but the best advice i could get was to cut the 14 wire and no one else knew hoe to fix it which sounds strange to me....how could this happen to so many sc's but no one know how to fix it...also about going inside the IRCM....well i did that too and i didn't have any build up of anything inside and you know its like rivited together so you'll have a fun time taking it apart....but you will get it if you want....but i don't know what else to say you said cutting the 14 wire didn't work for you....are you sure you cut the right one?..
 
Cooling Fan

What did you do to get the fan to come on manually. I am having problems with my fan also, but believe the problem might be in the motor. How were you able to check to see if the motor was your problem, or electrical?
 
Yup I'm sure it was the #14 wire, I followed the orange/tan (its kinda dirty so I cant tell exactly what color it is) wire that went right into the #14 spot on the IRCM.
If I have time today, I'm gonna rip apart the IRCM and see theres any buildup.
My motor is fine as I replaced it about a year ago.

To answer your question giinspector, you can check the motor by taking some wires and plugging it into the fan motor plug and then take the other end of the wires and touch them to the battery. If your motor spins then you know its ok.
To turn my fan on manually, I have it hotwired to the battery with a switch and 30 amp inline fuse so that you can turn it on anytime, I am not sure how to connect it so that it only comes on when the ignition is on.
 
Below is the wiring diagram for an 89, possibly the same as 90 and 91.

The only circuits involved are a fusable link. A line from the EEC. A line from the ignition switch, a couple lines from an electronic control assembly (?) and that's about it.

But note, all those feed into the IRCM. And as such, cutting the #14 wire should cause the relay for the low speed fan to trip, energizing that line. If not, it appears that the problem would be in the IRCM somewhere.

coolingfanwiring.JPG
 
I tried to get at the IRCM today and no luck. I was able to take the screws and rivets off to remove the outer plate. But this one bolt where all the wires go in will turn but not come out, I think its probably stripped. So without being able to remove that bolt, I cannot unplug it I have no way of seeing if the relay is dirty. Any ideas on how to unplug all the wires from the box?
 
Did you try to just unplug it. If the bolt turns, but not out, you can help it by getting your other hand in there with a screwdriver and apply some outward pressure to the head of the bolt. That will help it grip whatever threads it can and assist it in coming out.
 
A word of caution.....

If you modify the cooling fan (by putting in a manual grounding switch, or an adjustable cool fan switch), do not run the A/C unless you can be sure the fan is on. The cooling fan must operate when the A/C kicks on or the rising temperature in the condenser will cause the "head end" pressure to blow out the refrigerant from the pressure release valve. I found out the hard way.... If you use an adjustable "cool fan switch", be sure to also install the relay for the A/C fan control. (Flex-a-Lite has the complete setup).

Check on e-bay for an IRCM (just be sure it is for your model year, or at least close to it)
 
My A/C doesnt work and I think when it broke last year it was because of that reason. I remember it shooting out of the pressure release valve some smoke came out of the vents when it went. I didnt know the fan wasnt working at that time and had the A/C on. I guess that means my A/C probably has that black death thing now. I've unplugged the compressor so it doesnt come on with defrost because I dont want the compressor to seize. and mess my belts up.
 
It may not be as bad as you think....When I screwed my A/C up because of not "cooling" the condenser, I figured that the compressor (as well as the rest of the system) was going to need replacement. I took my SC to a guy (retired Ford Service Engineer who only works on Fords as a hobby) and all he had to do was replace the "lines and seals". It turns out that the pressure build up (he messured it at around 500psi) that blew the lines also blew out all the old refrigerant and compressor oil. He replaced the lines and recharged the system with R134 (oil and refrigerant). The A/C hasn't worked this good in years....
I had to reconnect my fan to the stock configuration, but I'm planning to go back to the adjustable fan switch as soon as I can figure out exactly how to wire a relay for the A/C fan control.
 
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