Q3 Q3 parasitic battery drain, any electrical gurus?

bagger_12

Registered User
Joined
Dec 17, 2012
Messages
84
Reaction score
1
Points
8
Location
Cornwall
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.
 

Attachments

  • B0EA6C82-978A-4044-B2D9-824C61F46BEF.jpeg
    B0EA6C82-978A-4044-B2D9-824C61F46BEF.jpeg
    448.7 KB · Views: 110
  • 9BF6E5F2-A2E8-41A5-85AF-428F502A33CC.jpeg
    9BF6E5F2-A2E8-41A5-85AF-428F502A33CC.jpeg
    993.6 KB · Views: 86
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?
 
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
 
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.
 
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
 

Attachments

  • 614B7497-AE06-4930-BDFA-0CB545120142.jpeg
    614B7497-AE06-4930-BDFA-0CB545120142.jpeg
    2.5 MB · Views: 68
  • B08EE488-F8AD-4F68-B558-DA9D04702A12.jpeg
    B08EE488-F8AD-4F68-B558-DA9D04702A12.jpeg
    1.9 MB · Views: 70
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.
 
  • Like
Reactions: bagger_12
Makes sense! Yes that is the thing I guess Il try a second hand climate unit then go from there
 
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.
 
Just buy a 2nd user one & test, ebay then if faulty return.
 

Similar threads