Another Battery Drain Saga - so far unsolved.

[horbrarian]

I've a 2007 PD VRS and havent had electrical issues until now. One of my sons informed me about a week ago that my car alarm was sounding.

 

I had a look out and used the fob to silence it, not really taking in that the headlights were flashing more dimly than usual.

 

The next day is was dead as a dodo, not enough battery to open the doors. I decided it was a false alarm with the windy weather and charged the battery overnight.

 

Next day - dead again! Charged the battery and went for a run, came home and heard the whine that sometimes continues for a minute from the engine. With the bonnet open, I could hear the whine being interupted by a relay - the load reduction one in the ebox. Replaced that, but no change. The only way I could get the drain to stop was to remove fuse F6 in the ebox. There seemed to be a little bit of water in there as well which was dried with a heat gun (low setting!). Thanks to Briskoda for that one.

 

The damn thing worked for a couple of days and then the drain issue came back. I'm now having to leave a battery lead off every time I park up.

 

What's driving me crazy is that the synptoms vary. I've had the fans come on after switching off, the whine at times and not at others, although it does seem to be related to the fuel pump also staying on. I've lifted the rear seat and can hear it.

 

I've got a version of VCDS and although I managed to log a scan, I dropped my ecig onto the laptop and now have a smashed screen. From memory, nothing came up about the fuel pump or any other of the parts displaying symptoms, just lots of "under voltage" warnings from the times the battery has drained.

 

One other oddity: I've one brake light out and the maxidot warns about that and a parking light. If I swap the brake light bulbs from each side, the corresponding parking light is reported as failed and the original one isn't reported.

 

Does this sound like a controller issue? I can't see how the fuel pump and the fans would be related.

[Vegasphil]

Is the battery not knackered? How old is it?

[horbrarian]

Sorry, meant to mention the battery. Bought last year, big solid one; rated at original specs or higher.

[Wardy]

Any changes to the car recently? Upgraded the stereo or anything like that.

Sounds very much like an open CAN gateway to me. Would be very useful to get a full VCDS scan from the car.

[Tilt]

I've got a version of VCDS and although I managed to log a scan, I dropped my ecig onto the laptop and now have a smashed screen.

Always knew smoking was expensive and dangerous.

 

That's unfortunate though, and also called sod's law. You try and save some money and it ends up costing you large.

 

Hope you sort both.

[Sarge]

2012 Scout at work has recently been returned from garage after having some sort of battery drain issue. I'll try and find out what the problem was and post up here.

[silver1011]

The brake light bulb is dual function, brake and tail.

 

Which parking (tail) bulb has failed, there are four on each side.

[studmuffin]

I've a 2007 PD VRS and havent had electrical issues until now. One of my sons informed me about a week ago that my car alarm was sounding.

I had a look out and used the fob to silence it, not really taking in that the headlights were flashing more dimly than usual.

The next day is was dead as a dodo, not enough battery to open the doors. I decided it was a false alarm with the windy weather and charged the battery overnight.

Next day - dead again! Charged the battery and went for a run, came home and heard the whine that sometimes continues for a minute from the engine. With the bonnet open, I could hear the whine being interupted by a relay - the load reduction one in the ebox. Replaced that, but no change. The only way I could get the drain to stop was to remove fuse F6 in the ebox. There seemed to be a little bit of water in there as well which was dried with a heat gun (low setting!). Thanks to Briskoda for that one.

The damn thing worked for a couple of days and then the drain issue came back. I'm now having to leave a battery lead off every time I park up.

What's driving me crazy is that the synptoms vary. I've had the fans come on after switching off, the whine at times and not at others, although it does seem to be related to the fuel pump also staying on. I've lifted the rear seat and can hear it.

I've got a version of VCDS and although I managed to log a scan, I dropped my ecig onto the laptop and now have a smashed screen. From memory, nothing came up about the fuel pump or any other of the parts displaying symptoms, just lots of "under voltage" warnings from the times the battery has drained.

One other oddity: I've one brake light out and the maxidot warns about that and a parking light. If I swap the brake light bulbs from each side, the corresponding parking light is reported as failed and the original one isn't reported.

Does this sound like a controller issue? I can't see how the fuel pump and the fans would be related.

I had exactly the same issues with my PD vrs a couple of years ago, even bought a new battery as I my old battery was over 5 years old and that still went flat...

The problem eventually traced to water getting into fuse box area..

[Gti Jazz Blue]

Is it still on the original alarm module as these have issues when the on-board rechargeable batteries reach the end of their life?

[horbrarian]

Sorry for the delay, been under the bonnet, working or phoning friends due to being stranded.....

 

Yesterday, I nipped into a supermarket and came back to the car giving it large with the fans and sucking electrons out of the battery like nobody's business.

 

I reckon that any voltage under a certain limit results in a no-start scenerio - to avoid the battery being depleted to very low voltages which could harm the battery. Luckily, I had taken a charger with me and managed to charge the battery up whilst playing guitar during a weekly musical/unmusical jam with mates.

 

In reply to  Gti Jazz Blue - it is on the original alarm module, can I just disconnect it?

 

studmuffin - I've gone to the trouble of covering the ebox with cling film then putting it's lid on, hopefully to avoid more H2O getting in.

Edited 18 December, 2015 by horbrarian

[horbrarian]

The brake light bulb is dual function, brake and tail.

 

Which parking (tail) bulb has failed, there are four on each side.

I'm pretty sure it reported "Front right parking light"

[silver1011]

Ah, so it wasn't a rear parking light?

 

Something is amiss then, if swapping over the rear brake light bulbs has an effect on which of the front side (or parking) lights work sounds very weird. 

[horbrarian]

Just to be clear, one brake light was defective and the same side front parking light was reported as faulty.

 

When I put the faulty brake light in the other side, the "faulty" front parking light also swapped sides.

 

Just to confuse the matter, with a new brake light in, it still reports a faulty front light, on the right side, the brake light fault is now cleared.

 

Didn't have time to check if the bulb is really defective as the battery ran out again. I'll keep going until I've tested everything.

[mannyo]

Check the alarm siren, its a common VAG fault.

 

My A8 is now on its third one at 11 years. The fault is the batteries inside leak and cause a short circuit and result in a flat car battery. The alarm sounder going off unexpectedly is an indication of this as well, especially if nothing is logged in VCDS as the leak bridges the trigger circuit.

 

The A6 I also have, has a dead siren but its completely dead now. The cars history shows the battery was replaced a few years ago due to unexplained drain problems.

Edited 18 December, 2015 by mannyo

[horbrarian]

Parking bulb replaced - thanks for the guides Briskoda!

 

No light faults now, Must have misread the faults, the right front parking light was definitely dead.

 

Going to investigate the alarm siren next.

 

Couldn't see it easily in the engine bay - is it hidden somewhere?

[erindad]

the alarm is under the o/side wing behind the splash cover , need to remove some screws to get to it.

[TsvRS]

Not sure I can contribute much but have a similar problem. After a long time standing doing nothing (first arguing with the dealer and then getting a new engine) my car had what I thought was a battery problem - never really kept charge. New battery improved things but even so after a couple of days the battery was only just starting the car. I measured the current being drawn from the battery with everything off and it was about 3.5 amps which makes sense in as much as that would be quite enough to drain the battery completely. That is a lot of juice though and I would expect to be able to see some evidence of it. I checked all the fuses and relays and it made no difference. Now I have replaced the alternator the drain current is 1.8 amps which is a lot better but in no way a complete fix.

I will definitely have a look at drying out the fuse box but am otherwise stumped.

Meanwhile I bought another battery which sits fully charged in the passenger seat-well with a set of jump-leads and that has gotten me out of trouble several times - pain in the ass when it is raining though ...

[horbrarian]

Not sure I can contribute much but have a similar problem. After a long time standing doing nothing (first arguing with the dealer and then getting a new engine) my car had what I thought was a battery problem - never really kept charge. New battery improved things but even so after a couple of days the battery was only just starting the car. I measured the current being drawn from the battery with everything off and it was about 3.5 amps which makes sense in as much as that would be quite enough to drain the battery completely. That is a lot of juice though and I would expect to be able to see some evidence of it. I checked all the fuses and relays and it made no difference. Now I have replaced the alternator the drain current is 1.8 amps which is a lot better but in no way a complete fix.

I will definitely have a look at drying out the fuse box but am otherwise stumped.

Meanwhile I bought another battery which sits fully charged in the passenger seat-well with a set of jump-leads and that has gotten me out of trouble several times - pain in the ass when it is raining though ...

 

Hi, that is helpful and I had considered buying another battery, which if it didn't solve the problem, would be useful in an emergency. The electrics are so complicated, no-one knows how they work fully, I build electronic circuits as a hobby and once tried to read the wiring diagram for the Octavia - it wasn't pretty. Even auto electricians rely on OBD scanners to tell them what's wrong.

 

I'll wait till Xmas madness is over, get a new screen for the laptop (grrrr!) and see what VCDS brings up, then perhaps test the current being drawn through different fuses as well as investigating the alarm unit.

Edited 23 December, 2015 by horbrarian

[Almal]

Passenger side heated seat, if your vehicle has heated seats.

[TsvRS]

Passenger side heated seat, if your vehicle has heated seats.

 

Mine does have heated seats - sounds worth checking. Thanks.

[horbrarian]

Sorry to report that this tale goes on and on....

I found that double locking the car (two beeps) seemed to avoid the battery drain. However, even this isn't stopping it now.

If the car is left for any length of time, it's so dead even the doors won't unlock.

 

As well, I have warnings that my passenger side "parking light" is out (although the bulb looks fine) and that the passenger side main headlight is out - which it isn't.

 

I've taken amp readings with a multimeter whilst pulling fuses and F6 under the bonnet seems to make a big difference; from nearly 1 amp to less than 50 mA.

The owners manuals give F6 as "Instrument cluster", but with the fuse out I just seem to have the "ESP disabled" warning on the cluster.

 

BTW, mine doesn't have heated seats and the bonnet fuse box is dry as I lined the top with a plastic bag before putting the lid on and left one of those silicon bags in to suck up any moisture.

[horbrarian]

EDIT:

Just tried it and it starts ok after a couple of hours - and the ESP light has gone out.

 

I noticed that with F6 pulled, the display cluster is off until I turn the key.

Perhaps that what "Instrument cluster" means for this fuse - it allows the cluster to be on after the ignition is turned off?