Hi,

Can anyone give me any insight on the cooling fan on our 2003 MPV. It kicks on almost immediately. Some days it kicks on right away other days it does not. The temp gauge reads normal and the engine does not feel hot when I put my hand near it. Doe the Temp Guage work off a sending unit in the block and the fan off a computer sensor?

 

You most probably have a faulty fan control module. This is the controller unit for the cooling fans. It is attached to the drivers side fan assembly. A black box approx 4 inches on a side and 1 inch deep. The side facing the raditor is silver with raised areas designed for cooling. See if a tap with a screwdriver handle on the side of the module makes the fan operation change.
This module should have been replaced on all 2002-2003 MPVwith an updated part as per Mazda SSP 60. Check with dealer or PM me with last 8 digits of VIN and will check to see if this program was completed on your van. This updated module was also replaced on same year V6 Mazda 6 and now part is being updated again for even more problems on 2001-2004 V6 Mazda 6 so hopefully you should be able to get the most recent updated POS.[:@]

 

The original fan controller on our 04 MPV lasted up until a couple of years ago. Got replaced by MazdOnly with a Mazda part. That lasted a couple of years, and it quit. So I replaced it myself with a Gates FCM102. Which lasted about 10 months. And now, no fan when hot, and no fan when AC is turned on. I just finished wrassling the battery out and replacing it with the only thing on Amazon that didn't have horrible reviews. NADA.

It's impossible to get to the wires with the battery in place.

I'm thinking the next step is to check the Gates FCM102 on the bench. But, which terminals are which? Nothing is marked. If I had the wiring and pins, I could both see if the old and new are behaving right. And test the fans.

 

BTW, I checked the two fuses marked Fan1 and Fan2, and both have continuity.

I guess another approach is sit the battery on the floor and use jumper cables to power the circuits.

Would I expect the fans to run with the ignition to On, and the AC turned on?

How about idling, but cold, with the AC on?

 

I got this diagram from Gates on their FCM102.

I'm trying to work out a wiring layout. Looks like the three conductor plug is input from the vehicle:

• 1C is ground;
• 1A is +12V, which comes from two 30A fuses which are wired in parallel. which seems weird.
• 1B is some signal, which causes the module to supply power to one or both fans. I don't understand from this diagram what that signal is or should be.

So I've got to take out the battery again, sit it on the floor, and use jumper cables to power the car while having access to these connectors. Fun, Fun, Fun.I guess first obvious test is whether we have 12V on terminal 1A; if not, then the cooling fan relay. If it is, then ... I can measure the voltage on terminal 1B; I don't know what is right/wrong. I guess I can ask Gates about that.Thoughts? It's a real pain to take this to MazdOnly and leave it and hitch-hike back home.

 

BTW, where the heck is the cooling fan relay on an 04 MPV?

 

Hmm. Maybe hiding underneath the front trim panel near the radiator? How convenient.

 

Nope. I now have no clue if there is in fact a relay supplying power to the fan control module. There is a relay marked PWM, but it is unclear if that is the heater/AC fan.