My problem is pretty much as my title suggests. One day, my fans kicked in (I believe its on low or medium speed) and it wont shut off, even when I turn off the car. This led me to believe that the thermosensor was the problem. So I replaced the thermosensor, which had no effect.

So now im wondering if the problem exists with the fan relays or the "cooling fan control module by the ECU" or somewhere else.
I searched , and found this on the scuderiaciriani website.

When the relays come on:

Relays 2 & 4 controlled by PCME, come on when temp reaches 221F.
Relay 3 controlled by thermoswitch, comes on at 226F
Relay 1 controlled by A/C switch.
How fan speed affected by relays:

Off, none on
Low speed comes on when relays 2 & 4 are active.
Med speed comes on when 2 & 4 are on plus _either_ 3 or 1 comes on but not both
High speed comes on when all are on.

Basically by connecting and disconnecting the battery, i can tell that the relays are switching on or off, but I cant tell which ones.
Since the fans switch on low or medium all the time (pretty sure its low) does this point to a problem with the PCME?

Any suggestions or ideas is appreciated

Ryan

 

You do know that the fan update will run the fans for 10 minutes after shutdown of the engine, correct?

 

You should only get the 10 minutes after shutdown if the car is REALLY hot. Like AC on and a hot day.

My neighbor had a similar problem - we swapped out the fan relays and he was good to go. Mazdaformance had a blowout of new fan relays a few months back for $5 for a set (no kidding) - I got 2 sets just because it was so cheap .

Anyhow, I've been planning on learning more about the fan system. My big gripe is the fan recall mod isn't documented at all - it's nowhere in the shop manuals or anything. I just like to totally understand the systems in the car - that's just me .

You do have the basic idea behind the fans right. 4 relays, 2 per fan. One relay for a fan on - low speed. Both relays - high speed.

It's gonna take some digging to figure out what's going on. Could be a wire shorted to ground, bad relays, a confused input in the fan control system (like it thinks the AC is on when it's not), etc.

Dale

 

Well, I figured if the location is correct, and he is in Hawaii....
It doesn't take much running under boost to get the temps up past 221F and trigger the module.

 

Assuming this isn't the fan 10 min. run-on recall situation......On page F-234 of the FSM, bottom left, it describes your situation of the fans being on constantly with the ignition switch set to ON, car running or not, and cold or otherwise. So your thermosensor avenue is the right track it would seem. Have you tried clearing the ECU since the new TS install? Can you swap out the ECU to verify the gremlin is not in the ECU? Was a "Fan-Mod" done on the car, and done well? A poorly done fan-mod, not grounding the lead off the ECU via a switch very well or that it is behaving somehow intermittently , would present your EXACT symptoms.

Just a few thoughts. Good luck and let us know the resolution.

 

Ok, update.

When i said the fan wont turn off ever, i meant it wont turn off ever. The fan would run even when the motor hasn't been running for hours. The only way the fan would turn off is when the battery died.

By the way my car had no fan mod, and I did try resetting the ECU before posting. The fans would stay on whether my key was in the ignition or not. Sorry if i didnt let you guys know : /

Anyways I found the problem. It appears that the wire leading from the relays to the ECU was shorted out and sending faulty signals to the relays causing the fans to run all the time. I changed the line, and the fans work the way its supposed to.

I'm also thinking of doing the "simplified fan mod", the one where you pull the AC relay, and use the AC to control the fans without having the compressor draw on the motor. This mod appeals to me in its simplicity, and you can change it back by simply plugging the AC relay back in.

It appears dale was on the right track in regards to my problem

Thanks for the comments.

 

it could be possessed! Dont rule that one out yet.

 

Glad you got it sorted out!

Dale