i recently have put in my own electric fan. i think it is a great mod, but now i am having problems with my a/c blowing cold constantly. the other day it was blowing cold from when i started my truck to when i got off of the freeway, then it didn't blow cold the rest of the trip home. i used a motorcraft fan rf-86, mounted in the factory shroud. the fan is switched on low speed by a radiator sensor, and the truck never runs hot (checked with test mode, runs around 182-186 degrees F). the fan is switched on to high speed with the a/c system, but it will not blow cold constantly if it is over 80 and i am not moving over 70 mph. any suggestions, my truck is an 03.

 

You sure it's coming on with the AC? Park your truck, and keep it idling then turn on the A/C to see if it comes on...

 

did you install an additional relay to turn your electric fan on when the AC is on?

if your AC is on and you are not moving much air through the front end, your air will not blow cold....

i have seen where tuners offer this extra relay as "optional"

IMO, its a must

 

Also while your checking that check that the fan is blowing the correct direction.

 

the fan is blowing the right direction. the fan does come on with the a/c. i made sure it turned on high when the a/c needs it, unless a wire came unplugged.

 

I had the same problem. My fans wouldnt blow cold at idle or in the city. Took me months to figure it out. I finally called my buddy , an engineer at Ford, and he figured it out. REM installed and had the fans wired backwards. Go figure. peace