mustangIIfan

hello again everybody its been a while since i posted, anyway i am in a 6 month battle with my electric cooling fan in a 2.3 5 speed LX the fan just wont turn on by itself. i have replaced the IRCM, the ECT switch, the radiator, and the fan unit. if i jump the fan to the battery it turns on. if i jump just the positive to the battery it turns on, so i know the fan and the ground are good. i had the car in the shop a couple months ago, and they jumped the ECT switch with a paper clip and the fan still turned on. they could not find any problems with the car. now i do not have the tools needed to test power to the IRCM but the car starts and runs normal so i must have some power going to IRCM since my fuel pump relay is also in there. somebody told me there might be a fusabe link blown? and he was not sure if i had one for it. where would this be if i do have one? i know there is a problem cause the temp goes more then halfway up and no fan turn on. the car has never overheated on my yet, thanks to the brand new radiator and it being over efficient. but the fan needs to work to be safe

onebadvert

Idk what your problem is. But you could always get an adjustable fan controller from summit racing. They run about 40-50$ and are super easy to hook up.

AlsCobra

How hot did you let it get? It should also come on when the A/C is on. It's a simple system but without a wiring diagram I can't really help you test it. If I'm correct, there's one temp sensor for the fan and a separate one for the fan. If you jumped the ECT and it came on, everything after that is working and I would call it ECT. without a multimeter and a hot motor, the ECT will be hard to test. Also check for trapped air in the cooling system. The sensor can't measure hot air.
Also make sure the thermostat is operating correctly. When hot, make sure both hoses are hot.

mustangIIfan

this has been a 6 month battle with the thing, i had the same problem last year and it was the IRCM it was replaced now its back again. i have replaced thermostat and bled the system several times i even had a shop bleed it. i have also tried an electric fan controller, with a probe into radiator and still didnt work. i did however today disconnect the harness connector going to IRCM and put a test light to pin 3 on the connector sparks came out and fan turned on, i then hooked a jumper between pin 1-3 and again fan turned on. the fan does not turn on with A/C but my air has been removed dont know if that makes a difference. temp gauge was more then halfway up def should have come on before it got that hot

mustangIIfan

great news guys, looks like i finally solved my cooling fan problem (HAAAZAAA). I spliced a 14 gauge wire into my 12v key on source in my radio harness (ill probably swap for a 10 gauge tomorrow) and ran that to the "power" pin on a 3 pin 12v 10 amp toggle switch, i then cut the positive wire on my fan and ran wire to the "acc" on my switch, finally i grounded the switch under my dash to the body. I turned the key and flipped the switch and boom fan turned on and ran normal, i switched it off and it went off, then i turned the switched on again and turned the key off and fan turned off. Ill probably run a fuse in the key on wire so i dont fry my system. I know its not a good idea to use toggle switch but it works for now and i can drive my car.

90mustangLX

This is what I did, ran it to a switch and used a relay between the fan and switch so I wouldn't burn the switch up, I'm running a sn95 electric fan