Fan issues

Fan relay is in the CCRM inside the passenger fender. If the fan is coming on then I don't think the CCRM is bad. Do you have a scanner that can read actual temp? Our gauges are kind of dummy gauges and don't matter a whole lot.

 

unplugging ther ect sensor is tricking the fan to come on hi speed. fail safe mode.
To test the fan circuit pull codes. one of the first things you'll hear is some relays clicking then the low speed fanfor a couple seconds followed by the hi speed fan for a couple seconds.
The guage in the car isn't accurate because it doesn't show exact temp. Install a real temp guage or at least use a laser thermometer on the radadiator hose or thermostate housing.

 

The CCRM has relays in it for low speed and high speed fan. I can send you schematics if you don't believe me. I don't know of any fuses in the circuit. My 98 does not have a fuse in the circuit for the fans, maybe that for the 94-95 cars?

 

I had similar issues as described in the first post, my problem was corroded wires and connector that went directly into the fan motor itself. Apparently that's not too uncommon of an area to become corroded, I'd check it out! If you find that you need a replacement id get a connector harness from a junkyard (that's what I did for a total of $2) or order this...

https://lmr.com/item/WPT362/94-97-Ford-Mustang-Cooling-Fan-Repair-Wiring-Harness

 

I don't know anything about the resistor, I don't remember that at all on my 98. I also have to add, on top of the corrosion those fan plugs like to melt. Pull the plug and inspect the connectors

 

Yes they do like to melt... Thanks for reminding me, mine was melted and the wires were exposed.... Which started the whole corrosion process I believe

 

I didn't say anything about a CEL.
Plugging in the OBD2 scanner does more than tell you why your idiot light is on. It also performs a diagnostic test on some of the electronics. IE the fan relays and CCRM.
Go get a HAYNES manual and look at the wiring diagram.
Remember the SN95 cars are different from Foxes. That may be where some of your wrong info is coming fom

 

Throwing a wild card in here. How old is your water pump and rad cap? I would plug a scanner and see when is the fan kicking on and if it correlates with data on dash board then start from the simple to hardest path. Mine does something similar but not as bad. It use to go to "A" in normal with 17yr old orginal rad/overflow cap but since I replaced it last summer it goes to "M" in normal when the car is stationary and is running.

Check: Radiator/overflow tank cap, coolant 50/50 mix, air in the system, waterpump, radiator, and electrical.