battery drain points to secondary water pump

[bryan89]

Hi all.
This is my first post. Working on a friends 99 VW beetle 1.8 turbo.

To start, her car is a piece of junk. everything is wrong with it. I am just trying to keep it on the road for her.

That being said, recently it has developed a battery drain issue. I have pulled and checked fuses. they are all good.

I put the multimeter on the battery with the ignition off and its pulling almost 1 amp. So I suspect its something in the car pulling it down, not the battery itself.

I further checked this by charging the battery overnight and disconnecting it. after several hours there was no battery drain and the car fired right up after reconnecting it.

Additionally, the alternator has been verified to be outputting voltage to the battery with the meter.

So I am pretty confident something in the car is pulling it down. and i am sure you would agree if you saw the state of this car.

I think I found the culprit to be the secondary water pump mounted on the back of the radiator. Now, I dont work on vws at all, but to my shallow knowledge i believe this pump is to circulate water through the turbo after the engine is off to cool it.
well, it doesnt ever shut off. i can hear it run for over 10minutes after the car is off. if i disconnect the pump, the battery drain immediately drops to approximately 23 milli amps which i assume is the radio or leds etc.

My question is, what causes that thing to run? i would guess a temp sensor somewhere tells the computer to run it until a certain temp is reached and then shut off. so maybe the sensor is bad? if so, which one and where the hell is it? i cant find anything in this little thing!!

thanks for the help
bryan

[bryan89]

anyone know what sensor makes this pump run?
maybe it runs off a timer somewhere?
any help in the right direction would be appreciated.

[Bluestream]

Fan control module

http://www.vwt4forum.co.uk/showthread.php?p=915553