Fan Control Module?

[Audibot]

My battery went dead because I accidentally left the heated seat on while it was on accessory and I was listening to music at my storage unit. I've subsequently had to jump the car a few times and she started right up each time.

Well the other night, I tried to do the same thing and then a bunch of smoke came from the front left of the car, down low. The only electrically-related thing down there I can think of was the fan control module. Has anyone seen this happen to theirs? Or is there something else down there I should investigate when I get to doing this?

I'm leery of trying to even start the car again for fear of an actual fire. I can probably disconnect it up top before swapping batteries to start it.

[ShelbyM3]

Is this on the RS6 or one of the Allroads?

I’d immediately suspect the fan control module, too. There isn’t really anything over there aside from that or maybe the fan itself. And as far as I can tell they’re all interchangeable so sourcing a new used one shouldn’t be too difficult. I’m sure there’ll be some evidence of melting if you saw smoke.


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[Audibot]

Allroad. Thanks. I am just amazed because I wasn't even trying to start the car at that point--it was just connected to power and the unit started smoking. I can steal one off my other Allroad, thankfully, but this just seems unusual--it's too cold for the fans to come on, unless the low rad hose fan switch is bad too.

[ShelbyM3]

During my cleaning adventures on my Allroad I tried to disconnect my fan control module and the connector was impacted with road debris and caked oil so I actually broke the connector trying to get it out. At that point I decided to clean it in place as best as possible and move along. With that said, I wonder if you've got water ingress or something shorting out the module and when it got power it got really angry? It is that time of year.

[Audibot]

Anything's possible. There is def oil caked up in that area so I would hope that protects it from water, but makes sense if there is a short because I had charged the battery before and it went dead quick enough.

I probably won't get time until next week at the earliest to look at it, with the weather predictions of rain and mixed rain/snow/sleet.

[V1nny]

they do die. $50 amazon chinese replacement seems to be working OK. Hurry before they get expensive :)

https://www.amazon.com/dp/B07MZV3K42

too late, already expensive

[Audibot]

too late, already expensive

$65 isn't too bad. But yeah it was def the FCM. Shorted internally so when power was applied, it would just heat up like no tomorrow, hence the smoke. No smoke after disconnecting it, but I haven't actually run the car. Will do that to raise the height when it's time to change it.

[V1nny]

I would not drive like that. It may also kill your battery, due to big current drain, which will be more than $65.

[Audibot]

Oh, I am not going to drive. I was thinking of idling long enough to raise up the suspension before shutting it off. It's disconnected so no current is going to it.

[ShelbyM3]

$65 isn't too bad. But yeah it was def the FCM. Shorted internally so when power was applied, it would just heat up like no tomorrow, hence the smoke. No smoke after disconnecting it, but I haven't actually run the car. Will do that to raise the height when it's time to change it.

Yikes. That concerning! You may want to inspect the harness for any damage, too.

I’m glad your car didn’t catch on fire! I’m curious what the mechanism of the failure was, though. I don’t want to suffer a similar fate. I do know both my 2.7’s the FCM is/was bathed in a nice layer of oily grime.


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[Audibot]

Probably moisture and corrosion but I won't know more until I do take it off. The lighter brownish on the outside of the connector remind me of coolant/water and oil mix. Could be a leak I didn't notice before.

This car spent the majority of its life since 2010ish (IIRC) in Indiana, and also did frequent trips to Mass and back. So much of its life in the salt belt, and at >265k, zero surprises anymore haha.

I'll have to fix the connector too--it's got that welded piece in it.

[V1nny]

these modules, particularly cheap ones, are not super watertight, so eliminating any leaks around it would be helpful.

[Audibot]

Anyone know what the name/part # of the black power connector into the FCM? I think I'm going to splice a new one on considering the melting. I keep finding smaller, 4-pin vs the 2 blade ones in my searches

[LZ9ROAD]

Anyone know what the name/part # of the black power connector into the FCM? I think I'm going to splice a new one on considering the melting. I keep finding smaller, 4-pin vs the 2 blade ones in my searches

4B0 971 955

Hope this helps, this is the large 2 pin connector.

[Audibot]

4B0 971 955

Hope this helps, this is the large 2 pin connector.

Awesome! Thanks! I might have a source on getting part of the harness and connector. This is great to have in case.