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Help identify pin #48 from PCM as signal wire from cooling fan control module

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My 2008 MKX (spare vehicle) was overheating. I have been working on getting this fixed for a while  

After the first over-heat, I noticed the cooling fans were not coming on - even with AC on full blast. 

So I test the fans direct to 12V and they both work.

Both 40 amp fuses are good. 

I know the fan control modules are a common issue so I concluded the FCM  was dead and ordered a complete unit (2 fans, radiator and FCM).

I live on a small island and parts take a while to get here so in the meantime, I wired the cooling fans to some relay's and switches so I can still drive it while I wait..

I received the parts and installed them - the first test I did was turn the A/C to max and to my disappointment, the fans didn't turn on. (damn)
So then I test the new fans direct to 12V and they both worked.

And this is where I am now...

At this point all I can think of is the signal wire from the FCM must not be getting power-  so I check for continuity, 
At the PCM, i see that pin #48 is the wire I need to check (apparently the 3rd pin over from the right)

according to this video - (fast forward to 16:20 mins)  -  https://www.youtube.com/watch?v=pXqpZoFxrbs


I test that pin with the signal wire on the FCM plug harness - like he did but there doesn't seem to be continuity.

So I further test - I open the wiring harness a little left to the PCM and find the white /BLU wire. And test that for continuity to the PCM #48 and it is good.
Then I test at the  FCM harness end - I find a white/BLU wire a few inches away from the plug and  test that for continuity with the signal wire on the harness - and it is good.

But when I test for continuity using the white wire a few inches from the PCM and the white wire near the FCM module harness, there is no continuity.

So either it is not the same white/blue wire or there is a break in the wire.

Final test - I tested the white/blu wire near the PCM (pin #48 according to the above video) for voltage and I get under 1 volt (even with A/C on full) - I understand it is variable.
And when I test for voltage on the White/blu wire near the FCM harness, I get a different reading. 0 if the harness is not plugged into the FCM - but I get 12 or 13V when the harness is plugged into the FCM.

So i am left a little puzzled...

Edited by MKX03
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First, did you install Motorcraft brand or some other brand.  Anything but Motorcraft can end up failing on you soon, or sooner at least.  I assume a new module was included with the new fans?  Tried using the OEM module with the new fans?



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MKX03,….. Did you ever figure out what the problem was? I’m currently chasing this same issue. I could really use your help/experience. Thanks. 

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