Odd electrical/locking issue

[beingdrained]

I have a really strange electrical issue with an 02 Golf. Most of the time it's fine. On occasion, it will have nearly killed the battery overnight, and it will be re-locking random doors at random intervals. I'm not sure if this is the cause of the problem, or a result of it. I've never caught it doing this after parking it, so I think it's either starting much later or only when the battery gets drained. Once it's started doing this, it will not stop until the battery is disconnected for a bit.

The only thing that's happened to the car recently is that several months ago I replaced the driver's side rear door. The original door has power window and lock, the replacement has power window but not lock. It seems like the issue could be related, but if it is why will it not happen for weeks at a time, then happen, and then maybe happen again the next day?

I've looked at various other issues people have had with both battery drain and door locks, but nothing seems to match up to this set of symptoms at all. Because it's so intermittent and unpredictable, it's very hard to chase down. I've set the door latch for a few hours and then done a parasitic draw test on the fuse box a few times, and nothing seemed out of the ordinary, but it may well be that the issue simply didn't happen to get triggered on those occasions. I'm mostly looking to see if anyone's seen this specific sort of issue before so that I can try to narrow the cause down in a more meaningful way.

 

[KrashDH]

I have a really strange electrical issue with an 02 Golf. Most of the time it's fine. On occasion, it will have nearly killed the battery overnight, and it will be re-locking random doors at random intervals. I'm not sure if this is the cause of the problem, or a result of it. I've never caught it doing this after parking it, so I think it's either starting much later or only when the battery gets drained. Once it's started doing this, it will not stop until the battery is disconnected for a bit.

The only thing that's happened to the car recently is that several months ago I replaced the driver's side rear door. The original door has power window and lock, the replacement has power window but not lock. It seems like the issue could be related, but if it is why will it not happen for weeks at a time, then happen, and then maybe happen again the next day?

I've looked at various other issues people have had with both battery drain and door locks, but nothing seems to match up to this set of symptoms at all. Because it's so intermittent and unpredictable, it's very hard to chase down. I've set the door latch for a few hours and then done a parasitic draw test on the fuse box a few times, and nothing seemed out of the ordinary, but it may well be that the issue simply didn't happen to get triggered on those occasions. I'm mostly looking to see if anyone's seen this specific sort of issue before so that I can try to narrow the cause down in a more meaningful way.

Are the only issues the locks? How about interior lights being a problem? The entire central lock/light system is tied into the harness that runs through the hatch. If you've never pulled the hatch boots, it's pretty common to find broken/corroded/rubbed wires that are bare which can cause all sorts of weird things. The length of wires and how stiff/brittle they got in old age didn't help the issue either.

Other than that, when was the last time you had your battery tested? I'm talking load tested, not voltage tested. That's another thing that can cause havoc in black-magic ways to a vehicle's electronics

 

[wonneber]

The only thing that's happened to the car recently is that several months ago I replaced the driver's side rear door. The original door has power window and lock, the replacement has power window but not lock. It seems like the issue could be related, but if it is why will it not happen for weeks at a time, then happen, and then maybe happen again the next day?

2X ^^^

Do you have VCDS to scan for codes and the door conditions (open - shut)?

Interesting the replacement door has power windows but not power lock.
I thought the power lock was part of the door module control.

If the controller thinks a door is open that may be part of it.
Even there the interior lights are fairly low power.

If the problem is that intermittent "weeks at a time" it may be tough to catch the problem.

 

[beingdrained]

Unfortunately I do not have VCDS. However, I would think that if the vehicle thought a door was open, the door ajar light would be on, as it is if a door is actually open. I know those switches sometimes fail, but that would seem to rule them out, would it not?

I have not tested the battery recently, but it does seem to be fine. When charged it will easily cold start the car repeatedly, and it's a 13 month old Interstate, so it seems unlikely to be bad.

I will take a look at the hatch wires. I could definitely see that being a possibility. I'll also try pulling the new door apart - maybe it does have power locks, and they've just never worked. That could explain the issue. I assumed it doesn't because it never activated and the lock is physically different than the other ones in the car, but maybe that doesn't mean anything.

 

[wonneber]

Unfortunately I do not have VCDS. However, I would think that if the vehicle thought a door was open, the door ajar light would be on, as it is if a door is actually open. I know those switches sometimes fail, but that would seem to rule them out, would it not?

I have not tested the battery recently, but it does seem to be fine. When charged it will easily cold start the car repeatedly, and it's a 13 month old Interstate, so it seems unlikely to be bad.

I will take a look at the hatch wires. I could definitely see that being a possibility. I'll also try pulling the new door apart - maybe it does have power locks, and they've just never worked. That could explain the issue. I assumed it doesn't because it never activated and the lock is physically different than the other ones in the car, but maybe that doesn't mean anything.

There's 3 microswitches in the door latch (iIrc).
I tried to figure what each does and -think- they are door open, door lock, and puddle light.

You have to take one apart to see what I'm saying.

 

[beingdrained]

I've played around with this issue more to try to address it. It's possible that the rear driver's side door lock is the issue, and I have another one from the old door, but I can't replace it because the hollow plastic pin that you have to pull to disconnect the window mechanism is stuck enough that I'm confident the glass would break before it came out. I still think the actual lock is unlikely to be the problem anyway, because of the following :

It's sitting there right now continually re-locking itself, but usually only the driver's side. It can't re-lock the back because the back lock doesn't work electronically. Actually playing with the doors and locks has no impact on this, it is in a state where the system is permanently convinced that it must lock the doors every few seconds no matter what. If one of the switches in the lock were the problem, then either the problem would always happen or playing with the door would affect whether the issue would happen or not.

From past experience, if I disconnect the battery for half an hour it will forget this and be fine, until it once again randomly (could be tomorrow, could be a month) decides that the doors must constantly be re-locked. More evidence that the actual driver's rear lock is unrelated would be that using or not using that door, locking or not locking it, or any door or any other part of the car for that matter has no impact on this problem. It seems to be entirely random. Pulling fuse 6 does nothing, and fuse 32 seems to only control the actual locks rather than the logic circuit that randomly decides it must constantly suck power and continually command a re-lock. Pulling fuse 14, the fuse that is shared between the locking system and the interior lights, will let it lock one last time after a random delay, then stop until that fuse is reinserted. Once reinserted, the horn does a quiet honk like the security system has been activated, and it begins locking the doors again randomly.

Anyone have any thoughts? In particular, I'd really like to know if this state of perpetually jamming the locks at random times is an intended state because of idiotic VW electrical engineering, or if there is a known specific way to trigger it?

Really wish that you could just properly disable things on this car. I'd just disable the entire electronic locking system and/or the security system and be done with it, they're worthless anyway. The engineering with simple systems divided into multiple circuits and intertwined with other unrelated systems is so bad.

 

[wonneber]

I can't replace it because the hollow plastic pin that you have to pull to disconnect the window mechanism is stuck enough that I'm confident the glass would break before it came out.

If it's the black (iIrc) pin about 1/8 inch diameter I used a drift to push them in and retrieved them once the panel was off.
Try it with the old door first.

 

[csstevej]

I use a long sheet metal screw to screw into the inner pin and pull it out with pliers , then I use a long 1/4 inch extension and tap the larger split pin in. Remove the window and retrieve the split pin.
I have done this several times as I’ve had to change the rear locks on both sides in the back....... First time doing is a little
unnerving .
When you go to put the window back in reinstall both pins in the window first, remove the black trim that goes across the door( where the window comes out of the door ) , engage the window into the track and snap it into place.

 

[beingdrained]

Thanks for the advice guys. I'll give it another try when I get a chance.

 

[Nuje]

Have you changed the lock module on the FRONT driver door? That's the one that sees the most abuse (open/close) cycles, and the little switch in there is prone to failure (see "$3 fix door lock" thread here) triggers a whole myriad of *** lock / alarm issues - all of which a major PITA because they're typically intermittent: sometimes repeatable, sometimes not, sometimes different.

Also, the CCM is going to be looking for and expecting a signal of some sort from the replaced rear door position. So, the CCM computer not "seeing" anything there could send it into some weird feedback loop.

I'd figure out how to get that rear door lock connected to the system again; if the glass breaks, it's easy and cheap enough to replace. Any wrecking yard will probably let you take the glass for ~$10 or less. See if that fixes, or even just changes behaviour. If it's still wacky, replace the front driver door lock module - replacements available for $30-$40.

 

[wonneber]

I'm curious, what was wrong with the door that was replaced?

 

[beingdrained]

The door was replaced because it was smashed by the owner.

Still have no solutions for this piece of garbage, but now the drain is constant and it's >500ma somewhere unfused on the interior circuit. Are there wiring diagrams available somewhere for these things? I've honestly never come to have less regard for the people who designed something electrical than this.

 

[wonneber]

Are there wiring diagrams available somewhere for these things? I've honestly never come to have less regard for the people who designed something electrical than this.

The Bentley manual has the diagrams.
Might have to search to find it.
The DVD version is:
Bentley Repair Manual DVD for Golf/Jetta (A4) VA45 | IDParts.com - Diesel Parts

 

[Nuje]

Are there wiring diagrams available somewhere for these things?

Like the man here says, $35USD gets you 24hrs to download all the wiring diagrams you like.