Sudden power drain while off

Geordi

Veteran Member
Joined
Jan 4, 2002
Location
Somewhere between Heaven and Hell. But it is reall
TDI
14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
Ok this is a new one... Went out to the wagon today to get something out of it, haven't driven it in a couple days. Battery was completely dead, reading 9 volts. It also was warm and I thought I could smell something like ozone, but that may have been a false positive b/c I was working on another vehicle doing wheel bearings and abusing an electric impact gun on that job.

Swapped the battery with a group 65 I had, checked everything, moved the car around a bit and everything seemed normal. about 3 hours later, THAT battery is dead too, pulled down to 11.0 volts.

The only odd things I have observed recently is a persistent door latch issue (doesn't read that the door is open, lights are never on / no chime for headlights) and when I hit the unlock button on the remote, the outer elements on the high brake light flash. With the hazard button, the outer LEDs of the high brake also flash. The starter bendix is also giving me issues (not holding the starter engaged to the flywheel) but it doesn't seem like that is the source of the short b/c tapping the positive starter wire to the battery doesn't show a spark. Doing the same with the lead to the fuse box DOES show power however.

I've replaced all the tail / parking lights with LEDs, but this battery drain just seems to have started today / the last couple days. The weirdness of the lights has been for a few weeks now. I have taken it on a trips to St Louis and Vermont in the last few weeks and other than the extreme cold, it was fine for the entire trips. Where do I start looking?
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
9v is really low, usually a dead battery will show 11.5 or so, When I've seen this on other cars, it's been an alternator internally shorted out. Whatever it is, it's a large wire connect.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
volt meter
Start checking mA Draw on each fuse you should find your problem
Also check with the fuse out, continuity from both left and right side of each fuse to ground.

Report back when thats done. i bet you find your draw, you have some funky wire issues that sounds like a wire shorting issue or relay feedback or some crazy VW thing.
 

Geordi

Veteran Member
Joined
Jan 4, 2002
Location
Somewhere between Heaven and Hell. But it is reall
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14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
I think I've figured out the lights, it seems to be related to the parking light sockets in the replacement headlamps. The socket tabs are too close together and are touching where they shouldn't be. I can take care of that easy enough.

Now for the battery drain - Is there any reason why the glow plug / fuel pump circuit from the top of the battery fuse box (S163) would be live when the key is out? Unscrewing that connection AFTER unscrewing the Interior Relay Panel (S176) showed a spark. It did it a couple times, and then stopped.

I also had a code in the system, I've been having a glow plug code 674 for the #4 plug, but today I had a new one pop up P0684 - Glow Plug Module to the PCM communication / performance. That would track with the observation, maybe a relay got stuck. Edit: Found the glow plug module, under the plastic by the windshield. Nice of them to bury it there... How the heck to remove that is the next challenge. I can definitely smell something electrical so I suspect that relay is stuck on.

And oddly enough, what I thought was controlling the lighting glitch isn't. The front sockets are removed at the moment so I can fix the definite issue there, but the high brake light STILL has the outer elements lit when the marker / parking lights are on. But it didn't come on instantly, it took about 30 seconds to a minute after I turned on the lights to check the socket. I don't understand the wiring in these things. Pulled EVERY BULB in the rear, and no change - so it isn't a wiring issue in the tail lights OR with my trailer lighting controller (Uhaul diode set) which I have also removed for the moment. Somewhere the power is feeding back to this. Maybe that same glow module, because hey, why not?
 
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AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
The fuse panel on top of the battery is always hot across each fuse, including the three green 30 amp fuses. The big red wire to that fuse panel keeps them hot (live) not the ignition switch. Notice that the black wire (same size as the red wire to the fuse panel) on the positive cable goes to the Alternator. You can disconnect that wire to see if the ALT is the issue but leave the red wire to the fuse panel connected.

Note: except for the starter power, all current for the systems in the car go through the fuse panel on top of the battery.

Fuses facing the panel, left to right

1. Fuse for the Alternator (150 amp)
2. Fuse for current going to the relay panel under dash (110 amp)
3. Fuse for coolant GPs (40 amp)
4. Fuse for the GP (50 amp)
5. Not sure what it goes to (50 amp)
6. Green fuse to the fan control module for the two fans out front (30 amp)
7. Green fuse to ABS (30 amp)
8. Green fuse to ABS (30 amp)

There is a contradiction in the Bentley with respect to the three fuses that are 40, 50, & 50 amp)... They are listed differently in separate sections of the schematics.

Hope this helps..
 

Geordi

Veteran Member
Joined
Jan 4, 2002
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Somewhere between Heaven and Hell. But it is reall
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14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
Andy - I know all those fuses are live all the time, thanks. However the circuits behind those fuses shouldn't be using any of that power because the circuit should be broken at the appropriate relays.

For the interior relay panel, that also controls the body computer so is active all the time. I expect a spark when connecting that one.

The alternator wire did nothing, showed no change.

The one that makes the difference is the fuel pump / glow plug relay wire, there is NO reason that should be sparking when connected with the key out! That means a circuit is being completed and power is being used - quite a lot of power.
 

Geordi

Veteran Member
Joined
Jan 4, 2002
Location
Somewhere between Heaven and Hell. But it is reall
TDI
14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
Got the windshield plenum off - had to use a puller as others have suggested to get the wipers out first.

The bottom of the module has a "bulge" that has obviously been melted through the plastic from the inside, and after the battery was connected for only 2 minutes (with NO key interaction) it was noticeably warm. Removed it and tried connecting / disconnecting the battery contact again, NO spark. Which means any active circuits are very low power (as expected) rather than a high drain.

The module also smells strongly of burned circuit and the large pin socket in the plug shows overheating / a bit of melting. I'm hoping I don't need to replace that, since it obviously still passes current and I don't want to have a bunch of splices where they can be exposed to weather.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
If there is enough melting and/or corrosion to cause any sort of cross connect, you must replace it, plus it could be bad internally. I'd clean that up, clean the fuse holder on top of the battery and check the radiator thermo-switch.
 

Geordi

Veteran Member
Joined
Jan 4, 2002
Location
Somewhere between Heaven and Hell. But it is reall
TDI
14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
I know the radiator thermo switch is working or at least doing something - when I was in Vermont with this car last week, the glow light was on for about 10 seconds! I've never seen it do that before, but it WAS 5 degrees at the time.

This failure happened yesterday in Florida however, apparently it just got to the point where something in that relay shorted out. The car has now been sitting with the battery connected all day, and the battery isn't dead. Yesterday, it killed the battery completely in about 3 hours - a HUGE power drain.

I don't look forward to trying to disassemble that plug, but I ordered a replacement from IDparts anyway since it was only $11. I agree, better safe than sorry. The module stinks bad enough that I'm pretty sure I wouldn't have had to wait long for actual fire to pop out of it. It's in the trash now instead of stinking up my house.

As for the weird brake light issue, I haven't been able to chase that down, but it is not really bothering me that much. I have LED lights all around, but disconnecting everything doesn't change it. Dunno where the problem is, but as long as it doesn't pop anything, whatever.
 

Geordi

Veteran Member
Joined
Jan 4, 2002
Location
Somewhere between Heaven and Hell. But it is reall
TDI
14 JSW DSG, 03 Wagon 01M, 400k and IPT performance auto!
Even when the LEDs that I had added were all unplugged? I only did the front lamps and the back housings - and they were all unplugged the last time I tested. The brake lights don't come on immediately, but do when either the turn signal lamps are engaged or the parking lights are on.

I've added load resistors to the front (since putting them in the back did nothing at all to the blink speed) so I'll see if maybe that somehow changes anything. But since the more critical issue is figured out, I don't really care much about this unless it gets worse somehow. This isn't affecting anything else, just the outside 1" segment on each side of the top brake light lights up in certain situations.
 
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