Battery Drain

NadaGasser

Veteran Member
Joined
Mar 10, 2002
Location
Green Valley, AZ
TDI
1999.5 Jetta TDI
Hi Folks! I'm a "newbie" and I've researched the FAQs linked from Fred's home page, and didn't see a problem akin to mine, so here goes.

Three weeks ago, I bought a'97 Passat TDI from its second owner with 96,000 miles. This car runs GREAT, and it is really "tight" .... Not a squeak or rattle anywhere. I truly love this car, my fifth diesel (3 MBs, and 2 VWs). However it came with a hidden problem. After about a week, I noticed the starter didn't seem to be turning over the engine as rapidly as it once did, so I measured battery voltage the next morning after the car sat overnight. Before a start attempt, the "standing" battery voltage was a miserable 12.45 volts! Badly discharged! So, I put my 6 amp-charger on it for 12 hours and took it to my local farm store for a battery load test. The battery tested fine! So, it became obvious that there was a current "leak" somewhere when the ignition was off and key removed (the latter a significant clue which I'll address in a bit ....). So, I started removing fuses one by one, checking with an ammeter for current flow. On the second to last fuse (no. 21 in my '96 Passat owner's manual with a pen writing "same as 1997" on the cover), I struck paydirt. This fuse services the interior lights, luggage compartment light, clock, power locks, alarm system, etc. I decided to run a test, so, with battery fully charged (12.65 volts), I did not replace this fuse and let the car stand overnight. The battery voltage in the morning was 12.65 volts. Bingo! But, it gets better than this, and this is where I need some help from the non-newbies. I have learned that the ignition switch in the off position, but with key in the lock, permits electrical draws from certain items: radio and the "electronic dash" (clock, odometer, etc.) When I pull the key out of the lock, the radio goes off, but NOT the "electronic dash". This is where my battery drawdown is occurring, but WHY? I've spoken with another TDI owner (2001 Jetta) and he says his electronic dash goes "out" when he withdraws the ignition key from the lock.

Can anyone "out there" give me a clue why my "electronic dash" stays "lit" when my ignition key is removed? Help please! Thanks in advance for a reply to this newbie!
 

MOGolf

Top Post Dawg
Joined
Jun 27, 2001
Location
underneath something
TDI
2001 Golf GLS TDI Reflex silver, rough road suspension and steel skid plate, 2004 Passat Variant, Candy White, rough road suspension and geared balanced shaft module, and much, much more. 2016 LR RR HSE TD6, 2019 Jaguar I-PACE
A wild guess would be a bad ignition switch. The part in it that makes contact to supply power to the instruments is stuck in the "closed" position.
 
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