Q3 Q3 parasitic battery drain, any electrical gurus?

bagger_12

Registered User
Hi all I’m having some bother with my Q3. It has a 2.1A drain on the battery. By removing fuses I narrowed it down to the climate control unit and then confirmed it by unplugging the unit itself with the fuse refitted giving me a perfect 25mA drain. The climate control unit has 4 plugs on the back so I’ve also narrowed it down to 1 of the 4 plugs by plugging them back in 1x1 until the drain reappeared. The plug in question has 7 wires, 2 of which go to the multifunction control module. Is the multifunction control module Audis terminology for the BCM (body control module)? Has anyone come across an issue like this before? I was hoping the 7 wires on the problem plug would just go to the flap motors making it easy to diagnose but the fact they go to a multifunctional module that probably controls half the car complicates matters.
 

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NHN

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Which year?

Which colour plug is the one in question & how many pins does that plug cater for in total, even if not all used?
 

bagger_12

Registered User
2013 and it’s the brown plug (C) not sure how many pins the plug is but it only has 7 used pins in it. They go off to air purity sensors, vent temp sensors and of corse the multifunction module
 

NHN

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Whats the actual wire colour as elsawin isnt denoting connector colours unfortunately.

Can you show me a pic of the actual connector & each pin is number marked in the plastic, maybe with a torch tou can see it, the out part slides of the inner, both plastic parts usually have pin numbers embossed.
 

bagger_12

Registered User
Whats the actual wire colour as elsawin isnt denoting connector colours unfortunately.

Can you show me a pic of the actual connector & each pin is number marked in the plastic, maybe with a torch tou can see it, the out part slides of the inner, both plastic parts usually have pin numbers embossed.
I’m not with the car right now but I have a picture of the wires and also my notes. Hope this helps.
The D at the top is my mistake and should have been a C
 

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NHN

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Orange brown is a bus wire mate, so if disconnecting that kills the draw, then a network signal is keeping the cluster on, thing is, is it a climate unit fault or another network connected module at fault.
 

bagger_12

Registered User
Orange brown is a bus wire mate, so if disconnecting that kills the draw, then a network signal is keeping the cluster on, thing is, is it a climate unit fault or another network connected module at fault.
Just borrowed a climate unit from a friends A3 and it’s cured the drain. Any idea if it might be repairable? Buying second hand would be a gamble considering they clearly go wrong.
 

NHN

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Just buy a 2nd user one & test, ebay then if faulty return.
 
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