Cooling Fan Control Module Shot - $600+!!!

[Stealth01]

For those that followed the FAIL of my attempted climb up Pikes Peak, when my car overheated because the cooling fans wouldn't come on, here's the resolution. Well...the diagnosis.

The dealership had to spend an hour plus time on the phone to determine it's the fan control module. THat's weird, since we put a fan control module on it from another MS6 and they STILL didn't work.

But whatever.

They want $412 for the part, and $186 in labor. After taxes, this will be over $600.

And I'm not sure it will fix the problem.

Sooooo...I am going to pick it up tomorrow, pay them the $98 they say I owe them for the diagnostic work, and buy a used FCM from a guy who wrecked his MS6. If that fixes the problem, then I sell the MS6 and probably never own a Mazda again.

If it doesn't then I will be sitting on the car and trying like hell to find out WTF is wrong with it. If I do, then I fix it and sell it.

This is ridiculous. 6 months out of warranty and a part like that brakes, and is REALLY expensive. $276 for a new one if _I_ order it online.

So...the MS6 remains out of commission, and will likely be sold as soon as I get this fixed.

FAIL.

 

[Stealth01]

Yep, I paid them $110 to tell me that MazdaUSA engineers are 100% certain this is a fan control unit failure and replacing that module will be the only fix.

However, we put a working control unit in the car that day, when the coolant was still at 243-degrees and the fans needed to come on. It didn't work.

Here's what the dealership service guys wrote:

"FAN CONTROL MODULE IS BAD P0486. 12V ON BOTH SIDES OF POWER OUT TO FANS. TESTED FANS DISCONNECTED OK. A/C ON PCM REQUEST 60% DUTY CYCLE PCM OK."

I declined their $400 part (which is $300 through the dealer in Denver and $244 through a parts store), because they wouldn't promise me that if it didn't fix the problem, I wouldn't be charged parts or labor. I'm not going to pay for their trial-and-error approach.

So this is where I'm at. I have to find someone else with an MS6 in the area so I can try THEIR control module, AND put my module in THEIR car. If both cars work, we can eliminate the dealership's approach. If mine proves to be bad, I have a line on a used one for a reasonable price. If not, then I have to have someone with a friggin volt meter try to find where the power gets cut off, causing the fans to not run.

I am thinking about buying an entire fan unit (fans, wires, clips, and control unit) and seeing if THAT will work, but I'm not sure the problem isn't off the fan unit, one one of the other portions of that electrical system.

I'm ready to drive this damn car off a cliff at this point. And ready to drink until I can't see straight.

 

[batou079]

Dude, im really really bummed to hear that you have had such bad luck with this car.
Sound more like you got a lemon. i understand your frustrations and reasons why you never want to own a mazda again... same way i felt about my ranger in the past. never owning a ford again (ford manufactured, yes i know mazda connection lol).

Have you tried the simple before the complicated like checking the fuse box, testing continuity from the fuse box and you say your fan unit does work however it just isnt being powered correctly? sux for sure.

 

[Stealth01]

Have you tried the simple before the complicated like checking the fuse box, testing continuity from the fuse box and you say your fan unit does work however it just isnt being powered correctly? sux for sure.

Fuses are good. Dealership service idiots report 12V both sides on power out from fan. But they got the fans to run when disconnected from the control module (in other words, connected them directly to the battery).

But when we put in a working control module from another MS6 before taking it to the dealership, the fans still didn't come on, even with the A/C on.

And of course, no one can access a wiring diagram for the MS6 because Mazda keeps them to themselves. The service adviser even removed the one that was attached to my car's paperwork before giving me the car.

This is ridiculous. Absolutely ridiculous.

 

[tunersteve]

Sounds to me like the problem is further upstream. Could it be a bad sensor or even a lack of signal back to the PCM for the fans to engage? If the FCM is good, and the fans work, then I'd go there. Without looking at the system I don't know exactly where, but that's the best advice I can give you.

I don't blame you for not wanting to pay for the T&E approach.

 

[Stealth01]

Sounds to me like the problem is further upstream. Could it be a bad sensor or even a lack of signal back to the PCM for the fans to engage? If the FCM is good, and the fans work, then I'd go there. Without looking at the system I don't know exactly where, but that's the best advice I can give you.

I don't blame you for not wanting to pay for the T&E approach.

Didn't their statement say they tested the PCM?

A/C ON PCM REQUEST 60% DUTY CYCLE PCM OK.

Or is there another PCM?

I'm told it could be the temp sending unit, too...which I have no idea how to test, or even where it is...

 

[tunersteve]

Didn't their statement say they tested the PCM?



Or is there another PCM?

I'm told it could be the temp sending unit, too...which I have no idea how to test, or even where it is...

My bad, I guess they did. After the FCM, where is that signal sent/sending from? If the PCM is seeing a temp, then I don't know if the sending unit is necessarily bad.

If anyone has the shop manual and can post the circuit, that would help out a lot.

 

[Stealth01]

My bad, I guess they did. After the FCM, where is that signal sent/sending from? If the PCM is seeing a temp, then I don't know if the sending unit is necessarily bad.

If anyone has the shop manual and can post the circuit, that would help out a lot.

Haha....the folks on that other mazdaspeed site have the shop manual, but the wiring diagram is apparently separate, and no one can find one. And, interestingly, the butt-monkey service manager removed the one his techs were using from the paperwork he gave me.

And since my temp gauge works, I think the temp sending unit is probably fine...I also get temps when I hook up a Dashhawk, so I think that confirms that.

The only thing I can think of is that there's a bad connection somewhere along the wires between the fuses (fuses and relays are all good) and the FCM. So I'm trying to get someone with a volt meter to help me check that.

Good thing I have a third family vehicle I can use in the meantime.

 

[tunersteve]

Haha....the folks on that other mazdaspeed site have the shop manual, but the wiring diagram is apparently separate, and no one can find one. And, interestingly, the butt-monkey service manager removed the one his techs were using from the paperwork he gave me.

And since my temp gauge works, I think the temp sending unit is probably fine...I also get temps when I hook up a Dashhawk, so I think that confirms that.

The only thing I can think of is that there's a bad connection somewhere along the wires between the fuses (fuses and relays are all good) and the FCM. So I'm trying to get someone with a volt meter to help me check that.

Good thing I have a third family vehicle I can use in the meantime.

I'm thinking broken wire from the FCM back to the chassis.

 

[Stealth01]

Yeah, something like that. Just gotta get that volt-meter thing going...

 

[Stealth01]

Interesting...one of the parts stores wrote back to me and said they doubt it's the FCM, too. They said to check the ETC, too, and that the harness may be damaged...which I checked already.

 

[Stealth01]

OK, well, Mazda corporate engineers, who assessed this was a fan control module issue, were









CORRECT.

Swapped a known good one into my car and both my fans came on. Put mine in the other car, no fans. When we did this before, we must have wired something incorrectly or incompletely.

So problem solved, now I have to decide how much $$ to spend to fix it.

 

[tunersteve]

Glad to hear you got some direction on it.

 

[KrGsMrNKusinagi]

Had a similar issue.. Car said it was overheating.. Well starting to get hot.. I had air in the lines. The Fans would not come on either but I got no check engine light or anything. But when I got the air out of the line it worked fine. Then again my Heater was not working either when it was doing that.

Sorry about your car

 

[Stealth01]

Well, HLLYWD6 sold me his used control module. Got it today, and after install, we have fan action! So the purple failboat is up and running again! Yay!!

 

[tunersteve]

Good to hear it's back up and running. You still planning on selling it?

 

[Stealth01]

Good to hear it's back up and running. You still planning on selling it?

Wife doesn't think we can be a two-car family, so right now, no.