Central locking oddity

[dvisor]

I've been having a few problems with my leisure battery going flat after a few days. It's either a duff battery or a drain somewhere. Anyway, when the LB is flat, the central locking won't work, either from the plipper or the key. OK - that's because its on one of the fuses that's patched through to the LB - no problem there.

I took the LB out a couple of days ago to recharge it (at which point the CL wasn't working). This morning, I went into the van to do a few bits and pieces (LB still not in vehicle), and the central locking worked a couple of times Now its stopped working again. Any ideas as to what's happening?

[jaylee]

The old drivers door loom??
The manual factory system should at least work independent of what i assume is an after market remote...
So i would check (with the key in the drivers door) that first.
Especially as it sounds intermittent.

But then i would have thought the remote box would have at least just opened the drivers door...
Check yer key fob battery ain't on it's way out or dislodged & the power & earth to the CL control box too!

Hope this helps!

[g8dhe]

and the central locking worked a couple of times Now its stopped working again. Any ideas as to what's happening?

Did you have the engine running ? In which case the charging relay will have pulled in and the circuits were being fed from the alternator & S/B.

[dvisor]

Hi - no the engine wasn't running (and hasn't been run since getting back from the bash). LB was pulled out on Thursday morning, at which point the CL wasn't working (had to open individual doors manually with key). Didn't bother checking the CL this morning when I went into the van - simply unlocked the sliding door manually, and shut it when I left - the motor soft shut the door. Then without thinking I locked it using the plipper. Realized it shouldn't have worked, so tried it again and it unlocked. Then I went to drivers door and locked it with the key, and the central locking locked all doors (the central locking only ever works from drivers door). After that, neither the plipper nor key activated the CL again. I don't think its the driver's door loom, because the driver's door wasn't opened between it working and not working, so the contacts wouldn't have been disturbed.

It's almost as if some charge has built up over a couple of days from somewhere, enough to power the central locking a couple of times before being completely discharged again. But I really don't understand how. It's not a problem, but I just wonder if its related to my LB problem.

[g8dhe]

Its sounds like the remote receiver normally fed via fuse 1 is connected to the L/B, but it is also fed from a 30/40 Amp fuse from the under bonnet fuse panel - 16. Its not uncommon for a back path to exist that can charge up a capacitor and can give enough life to the circuit for an operation or two, and then it will need a little while to charge back up again before it happens again - just don't rely on it!

[dvisor]

Its sounds like the remote receiver normally fed via fuse 1 is connected to the L/B, but it is also fed from a 30/40 Amp fuse from the under bonnet fuse panel - 16. Its not uncommon for a back path to exist that can charge up a capacitor and can give enough life to the circuit for an operation or two, and then it will need a little while to charge back up again before it happens again - just don't rely on it!

Thanks Geoff - I guess that would explain it .

LB's back on again now and trying to find the drain. Only thing I can find is the clock bulb which is drawing 0.13A, but by my amateur calculations that would take a month to drain the battery. Removed and will see what happens anyway.

[bongolow]

I've been having similar problems and my central locking behaves the same as yours when the LB is flat (that is, it doesn't work, and I've not had the 'worked a couple of times' phenomenon).

There's a drain of 210mA* on mine but I've not had a chance to investigate further yet (I don't have a clock). I'm away for a couple of days but I'll look into it later in the week.

* at least that's what it measures on two different digital multimeters. However, I connected an old type analogue multimeter which has maximum current range of 250mA and the needle kicked hard over, well over the 250mA mark. Scratching my head over that one...

[g8dhe]

Scratching my head over that one...

A lot of the meters require you to plug the +ve lead into a separate socket(s) for measuring current as well as turning the switch, if you have left it in the usual V/Ω/low current then you will get odd readings. If you really are only drawing 0.21 Amps I wouldn't get worried at all, that's typically 16 days before the battery is totally flat.

[bongolow]

A lot of the meters require you to plug the +ve lead into a separate socket(s) for measuring current as well as turning the switch, if you have left it in the usual V/Ω/low current then you will get odd readings. If you really are only drawing 0.21 Amps I wouldn't get worried at all, that's typically 16 days before the battery is totally flat.

Thanks Geoff. Actually I was a TV engineer in a previous life (anyone remember valves?) so I know about the socket thing... . It could be just the meter - it's a cheapo Japanese thing and at least thirty years old so I don't know how accurate it is (hardly ever used it on amps). Seems pretty accurate on volts though. The highest range only goes to 250mA but it's got a separate socket for a 50 micro-amp range (like I need to measure micro-amps.. ). I have a mate who's still got an old Avo 8 so I'll borrow that, just out of interest.

My battery went flat in less than a week - maybe it's knackered but it's less than three years old so it shouldn't be. Trouble is I've got the radio wired to it so I lose all my presets when the battery goes flat...

[g8dhe]

Actually I was a TV engineer in a previous life (anyone remember valves?)

Ah ha, and yes only too well, I have a job seeing the latest SMD and that's not just down to the glasses I would agree the battery should last at least three years as a L/B, unless its been really hammered which it doesn't sound like. Time to get yourself a new meter from Maplin perhaps, I must admit I do keep a small cheap one in the van in the toolbox.