Engine cooling fans won't stop

TDIfor

Veteran Member
Joined
Aug 20, 2003
Location
Logan, Ohio
TDI
'02 NB Double Yellow
Gentlefolk;

'02 NB TDI 5Sp 178K miles

When I turned off the engine today after coming home from work, in 90+ degree weather, with A/C on, the engine cooling fans continued to run on high. I finally had to disconnect the negative battery cable.

This happened before, and eventually it stopped... it only hiccupped like this a couple of times.

In trying to track down A/C issues a year ago or so, I swapped out the fan control module, so there is a newer FMC in there.

If the FMC is sound, is there another relay there that could be flaking in the high temps?

Thx!

Don
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
The max after run time is about 10 minutes, and if it is really hot under the hood it can after run for that long, but not usually on high I would not think.

I'd try another fan controller myself if it keeps happening.
 

TDIfor

Veteran Member
Joined
Aug 20, 2003
Location
Logan, Ohio
TDI
'02 NB Double Yellow
I reconnected the battery after the engine cooled down last night, the fans started again.

When I reconnected the battery cable this morning, the fans fired off immediately.

Geesh..I hate swapping out FCMs in the NBs.

Well, I have an old one that was still working kicking around. Will drop that in to test.

Thx!
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Not sure how you are getting to it, but I find it easiest just to take the battery out, then the tray. Not hard, but does take a few minutes.
 

TDIfor

Veteran Member
Joined
Aug 20, 2003
Location
Logan, Ohio
TDI
'02 NB Double Yellow
Not sure how you are getting to it, but I find it easiest just to take the battery out, then the tray. Not hard, but does take a few minutes.
Yeah, that is the way I get to it too.... you forgot the tricky parts... removing the battery blanket - harder than seems likely,for some odd reason, and loosening the power steering pump, and cataloging all the bolts so they go back in the correct spot, and removing the battery without having it arc across the body panels, breaking off the locking tab on the FCM electrical plug... I think I have the R&R process down to about 45 minutes now. But it is still not my favorite task. Well.... in fact I have not yet found a favorite task regarding the innards of my Bug....
 

TDIfor

Veteran Member
Joined
Aug 20, 2003
Location
Logan, Ohio
TDI
'02 NB Double Yellow
fan switch in the radiator

<blank look>

WHAT fan switch in radiator????

Anyway, the Bug has cured itself. The fans were working normally today. But I like the fan switch idea, since the FCM is fairly new. How do I find this thing?
 

joetdi

Veteran Member
Joined
Mar 8, 2008
Location
Midwest
TDI
2-2002 Jettas W/Auto
You might have a problem with an open circuit at times feeding fuse 16 to the FCM. If that circuit opens the FCM will runs the fans and do so until the battery is dead.

I had one with a broken wire a while back doing what yours is doing.
 
Top