Electric fan Issues....

[Shadowfangs]

Ok all, So i dont come here much. And I havent worked on my mustang all winter. Today was really nice outside so I decided to start working on it again. Im having some issues with the cooling fan not working. It does not come on when i turn the A/C to max, It doesnt come on when the temperature gauge goes past the L in normal, bordering into hot. The car starts, it runs, it idles. The fan Works by itself I have verified both speeds work. I Jumped 12v to each wire individually while having a ground hooked up to the black wire. One is slow, one is Fast. The temperature guage works properly and have verified it works with a fluke IR thermometor. The Haynes book is absolutley NO help. I've checked all fuses and relays. Im pulling my hair out over this one.

I also got a CCCM (ford calls it a Multi function relay) to replace the one on my car because it was damaged (Dented box, rusty all over)

Here is something Pecuilar though. I for one reason or another, had the key on and the AC switch on max (engine not running but was still hot from trying to warm it up) And I started to change the CCCM, While unscrewing the bolt that holds the plug into the box, I can tilt the plug to where only most of the top pins are connected and the fan came on! Of course when its plugged in correctly it doesnt come on at all. Can someone give me some advice where to start tracking down this bug? I really dont want to have to take the harness apart and go over each wire one by one. Thanks for taking the time to read this!

Charles.

 

[two95s]

ECT sensor?

 

[Shadowfangs]

Hrmm... There are two of them arent there? Even if that was bad wouldnt the fan still come on when I switch to max/ac? I dont have any freon in my AC system and currently have the compressor unplugged.... will that prevent it from working as intended?

 

[Shadowfangs]

Bump?

 

[Shadowfangs]

Allright, searched all day and night for some info no the interwebs. Found the problem. I unplugged both the ECT sensors, the fan came on! High speed. I plugged the passenger side one back in, fan stayed on. Gauge started working again, Then, I plugged in the driver side ECT. Guess what, Fan shut off. Guage still worked, but the fan shut off. So, got the ohm meter out, the sensor registered 5.5k Ohm .... Ford says when the engine is cold it should read 74 ohm and once it is up to operating temp it reads 9ish ohms.... My ECT was bad... Replaced it, let the car warm back up and fan comes on by itself. By the way, If you have No freon in your system, the Max/AC trick to bring the fan on will not work.

Thanks all! Hope this helps someone.