2000 Windstar 3.8 cooling fan malfunction

[usstitanic]

My 2000 Windstar cooling fan on the passenger side is running all the time when I am driving, even in freezing temperature. My gas mileage goes from 18 to 13 now. Any troubleshooting help is appreciated. Milton.

[wiswind]

So...only 1 fan is running all the time?
I do not have access to wiring diagrams for your year.
The fans will run with the air select to AC or Defrost.
I do not think that your fans will impact your mileage to that extent.
I cannot think of any situation where only 1 fan would be running....BOTH should be running or not....so THAT would be an issue right off......

I know that I am not offering much help....
I have a membership with Alldatadiy....but your 2000 is different from the 1996 that I had.....so my wiring diagrams will not be of any help.

[tomj76]

A cold engine will get lower MPGs, due to a rich fuel setting. However, the thermostat should keep the engine temperature in the normal range, even if the fan is running all the time.

In my '96 there are two relays that control the fan, one for "low speed" which is used when the AC is on, and one for "high speed" that runs only when the engine temperature exceeds a limit. When operating in low-speed mode, the fans will turn off if the road speed exceed 50 mph. The fan relays are operated by the PCM.

The electrical current for the low speed setting passes through a "dropping resistor" to lower the voltage on the fan motors for the lower speed.

If you need to find the resistor, it might be mounted somewhere in the front of the van. On my '96 it is located under the passenger side head light. The resistor is a about 2" x 3", white ceramic, and in a "U" shape. There is an electrical connector on it.

Check the voltage to the fan motor. The voltage drops to about 6 volts for the lowspeed setting. In the high speed setting the voltage will be 12 volts. The PCM grounds the relay coil to turn on the fan. There could be a short in your system that is turning on the relay without the PCM. It is also possible for the relay to stick closed. The relays are housed in a module called the CCRM which is located under the battery in my '96.

[usstitanic]

Thanks for the quick reply. I will check the 12v circuit for the fan and make sure there is no short.The fan for the air cond is working fine when air cond is on. However the other fan is in high speed all the time. Will there be a malfunction temperature sensor to tell the PCM to turn on the fan?

Milton.

[scubacat]

Check the AC pressure line (or "transducer") screwed into the freon line right near the little muffler-like part in the front. Look down just inside the radiator to see it. It has an electrical connector on top. If that fails, it'll constantly run the condenser fan (the right one) just like you're experiencing. I had to replace mine a couple of years ago.

The good news is that there's a schrader valve underneath it, so you can just unscrew it and screw it or a replacement right back in without evacuating the system.

[usstitanic]

Thanks for the reply Scubacat. What do you call that part? Is it a pressure sensor?

Milton.

[scubacat]

Check this link. (The first part in the list is not correct.) It's the one with the long plastic connector and the metal fitting that screws into the port with the schrader valve on the little muffler-like part on the line.

http://www.rockauto.com/en/catalog/f...re+switch,4656


I would urge you to test this out first and not just dive in and replace it though. Maybe unplug it and see if anything is different (like both fans kick on instead of just the one). Also, try and get some live data and see if there's any way to tell if something completely different is causing this. I can't find any diagnostic information on this part in the workshop manual but I'll dig a little more.

It could also be the coolant temperature sensor, although I'm pretty sure that would turn on the LEFT fan first. (I may have this all backwards, though. I'm a little tired...)

[usstitanic]

Thanks scubacat!!! I will tackle this later on. I have to take care some urgent issues first; the heat pump failed last night and I have a water leak inside the wall in my house. Sh****t happened all at one time. This weekend is ruined.

Milton.