05-13-2015, 09:36 AM
Join Date: Jul 2013
Location: Philadelphia, PA
What I Drive: 2002 Black SVT
FF Reputation: 1
Buy-Sell-Trade Rating: (0
The infamous Cooling Fan Bug round two
Before we go there... yes I am aware of all of the other posts pertaining to this issue. I've been through them a few times now.
Here's the quick back story. When I first got this car I replaced the t-stat and housing. Couldn't get the cooling fans to turn on after refilling the system. Went through and replaced all of the common parts (relays, fuses, fan resistor, temp sensor all new, and checked the fan motors). The fans came on low with the A/C on, but would not come on automatically at 90C like they are supposed to. After popping the hood to show the problem to a buddy, all he did was squeeze the upper radiator hose to feel the temperature of it... and the damned fans turned on once it hit 90C. Good to go from there on out.
Fast forward 2 years, did a timing belt/water pump job recently and I'm having the same problem again. I went through and checked all of the same components, everything looks good. Anybody have any suggestions here? There seems to be some debate at what temp the fans should turn on at, does anyone have the word from Ford on this one? 90C for the low speed?
If this is of any help... the fans turn on high when the temp sensor is unplugged. If I jumper the two pins of the connector together, nothing happens and the fans stay on. Plug the connector back in to the temp sensor and the fans turn off again. Shouldn't the full voltage or zero voltage from jumping or opening the connector trigger a change in the signal?