I have a feeling the Viscous Fan Clutch may not be working properly. this was an aftermarket i put in quickly 3 years ago. it's possible that is the culprit.

I checked the Electric fan and the 40A is fine. Not sure how to test the relay in the same engine compartment fuse box.

 

I have a similar challenge in getting my electric fan to run under the circumstances specified in RAVE. You can test the fan motor and fuses in the truck by removing the relay and with the ignition on, jump the relay. Fan should come on.

My understanding, (and where I'm at now incidentally) is that this leaves the senders and the relay itself as possible points of failure. In my case, my fan never comes on under any situation so I'm going to start by replacing the relay, then by looking at the senders and wiring which provide input to that system to tell it to operate.

 

This morning I found my problem. The electric fan works fine with AC on. It's the Viscous Clutch and main fan. the fan is very loose even when hot. Waiting for part today. How can I missed that? I have been fishing wrong places.

 

SayeedA congratulations on finding the problem.

I scrolled back and I don't see what year your truck is but if you are going to spend a little money you might want to do an electric fan conversion. Alex M has a thread on a Ford Taurus fan, I think. I tried an expensive fan setup off eBay and it made my truck overheat.

If not you probably want the older style fan (with the ring around the fan, as opposed to open blades) because you can change and upgrade the clutch.

 

Truck is 2001 with 85k original miles on it. I am the only owner. I already ordered Hayden 2991 clutch and original D2 fan blade. I changed my original one with an aftermarket fan and clutch (din't know much at the time). Parts should be here today I will do some research for the conversion down the road. I never had this problem before until now.

Thanks

 

I was curious as to the redesigned one piece fan blade/clutch performance vs the 99-02 fan blade/removable clutch performance. I slapped on a used 03 setup onto my 99 and monitored the temps via my scangauge II. They were 1F degree apart at idle, but on the road it seemed the one piece unit ran 2F cooler. Both units are of coarse used, with almost the same mileage on them. So after my little experiment I see no difference between the two. The two piece design is the way to go cost wise and being able to find a replacement clutch locally (my auto zone's always have a quality made in the USA unit in stock).

Just wanted to post my test results if anyone else was curious like me.

 

Has your D2 been cooling properly since changing the fan clutch? With AC running? What is the temperature differential between AC running and AC off? My engine temp will go up 5-10 deg when AC is turned on. I'm wondering if the system is maxed out, or if the condensor is faulting

 

yes, that was my problem. clutch was completely shot. I have not really took the temperature reading but it stays in the middle like always did. I should probably start looking into the temp.

Thanks

 

even if the indicator of the temp gauge is reading "normal," "average," or what have you, the operating temps could be as high as 240-250 degrees. At that point, after it is WELL overheated, will it then begin moving up toward "hot," "overheating," whatever your best description is.