Fuse #42 my battery drain problem on 2005 A4?

tupdegrove

Active member
Joined
Jan 13, 2012
Location
Allentown, PA
TDI
2005 Jetta TDI PD Auto
- (A year ago before these problems, both left-side lock mechanisms were replaced due to an "open door" problem. Door issue seems fixed. Car was being used several times a week.)
- Three year old Duracell battery replaced (Sam's Club tester won't even print), 2+ months later it's dead again (< 5V) and replaced, and 2+ months later (today) now car wouldn't start (just barely turned over; measured 11V). When having trouble during this time, the common theme is that the car has sat for exactly one week. Car was locked, key not in ignition, no lights left on (verified visor lights were off). Searched and read a few similar threads. Started new thread to keep from hijacking their threads.
Used http://pics.tdiclub.com/data/500/TSB..._04_Matrix.pdf to measure fuses #24-44. Didn't know how to measure fuses with door closed so kept driver's door open with all interior lights off except for light on driver's door. Key not in ignition.
#42 (25 A; radio) = 0.6 mV = 281 mA. Noticed lights were flashing on PhatNoise disk system (left side in trunk). Lights stopped flashing after replugging "disk" and now measured 0.5 mV.
#38 (15 A, central locking system) = 0.1 mV = 23 mA
Is #42 my current drain problem? A little hard to feel the amp in the truck with the cage but it didn't feel warm.
(I tried to measure the total current drain by removing the negative battery terminal and inserting an amp meter but it didn't seem to work. I suspect this was because I connected a power source to the OBDII to keep from losing the radio code which I don't have. Can dealer give it to me?)
 

tupdegrove

Active member
Joined
Jan 13, 2012
Location
Allentown, PA
TDI
2005 Jetta TDI PD Auto
Charged up battery to 13.25 V (40 degrees). Removed fuse #42. 17 hours later measured 13.07 V (30 degrees). Agree circuit #42 was the problem? Comments welcome.
(Just remembered I didn't lock the car for those 17 hours so I should probably repeat test.)
 
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