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Discussion Starter #1
So I originally noticed the A/C would have a high dip in the idle about 3-4 seconds after turning on max A/C. After looking at it and comparing to my Cobra, I could see the fan was not turning on at the same time the A/C was, it was delayed (where my Cobra they came on together). This seemed to catch the idle by surprise (IAC and PCM) and cause it to feel like it was going to stall.

I then checked the engine temps when the fan was coming on via obd 2 tool and could see it go to 226f and cool down to around 219f (really hot!). That is the high fan range and clearly do not see the low fan turn on like it should when it should. So after doing some internet research, here is what I tried so far and the results:

Unplug the ETC sensor and the fan comes on right away no matter if cold or hot
I got the service manual and looked at the wiring harness. I checked the aux fuse 30amp right by the mass air sensor which is supposed to be a breaker for the low speed fan. It was fine.
I checked the other fuses, they seem fine.

With the ETC sensor unplugged (fan running), I checked the following things:
- Tested the orange (high speed) fan wire and it showed 13.5 volts
- Tested the red (low speed) fan wire via backprobe and I could not get a signal (assuming the backprobe was in correctly)
- Tested the 30 amp fuse on both sides of the fuse, nothing

So seems like nothing is going down the low speed wire to the fan from the CCRM

So I think this only leaves:
- CCRM (most likely)
- Wiring (looked things over, seems OK)
- PCM (not very likely)
- Some strange ground on the electrical (but I cleaned every last one I could find on the car about a year back including ground strap)

Thoughts? Am I far enough to just replace the CCRM as the most likely cause?

Next, if I need a CCRM, I am on a budget but need it to last reasonable enough. Thought I have seen people way they were happy with Cardone rebuilds. Was also considering used, but I might just end up where I am now. Ford OEM is likely too $$$ for me at the moment (but of course likely the best part).

Thanks in advance.
 

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Discussion Starter #2
Thoughts?
 

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look at the wiring diagram

you will see the low speed is always on, and the ecm turns it off

that should be a good hint
 

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Discussion Starter #4
Update - It seems my prior observations were wrong. I guess I could not backprobe the fan low speed connection well enough. I retested everything (had to pierce the wire) and found:

- The red low speed fan wire does have power at 216F (14 volts) until the high speed fan comes on at 226F. So we have low speed fan voltage from the CCRM, but no fan.
- The 20 amp fuse next to the maf sensor also has the same voltage and behavior.

So since I am seeing power turn on at the right time for the low speed fan at the fan connection, it must be the fan low speed motor. So I am going to order a new cooling fan. I think that will get things done.
 

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I would confirm that 100% first

high resistance in the wire from the CCRM to low fan pin on motor will give you voltage on the wire, BUT<, the wire may not be able to carry the current

bypass the ccrm circuit. run a proper sized wire to the low speed terminal straight from the battery and see
 

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Discussion Starter #6
So I had already ordered a new fan. So I went ahead and threw it in today. Things are now working great! Low speed fan now turns on at 216F and off around 203F (no more high speed fan turning on around 226F). And the A/C no longer has a erratic idle due to the high speed fan turning on late (since no low speed).

Thanks for all the advice.
 
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