Windows going up on their own.

[P S K]

Every so often, both windows will wind up on their own as I'm driving. This will happen 2 or 3 times in a 2 hour trip

Have reset door control box by unplugging, leaving for 10 mins then reconnecting.

The only way that the door control box knows when to close windows is when it receives a signal from the alarm unit, which was replaced 3 months ago. Have contacted the supplier of the alarm unit and they don't want to know!

Any ideas?

[ridds]

Dppr reed switch.

Bet the little green light on the "disarm outside door buttons" flashes as well.

When the reed switches fail or get a dodgy signal they really do cause havoc.

Also, until you fix it, don't leave the car running with the keys in it and it running. Nearly got me once but luckily the boot was open.

[P S K]

ridds said:

Dppr reed switch.

Bet the little green light on the "disarm outside door buttons" flashes as well.

When the reed switches fail or get a dodgy signal they really do cause havoc.

Also, until you fix it, don't leave the car running with the keys in it and it running. Nearly got me once but luckily the boot was open.

Thanks.

Will check switches tomorrow. Good tip about leaving it running too!

[ukkid35]

Has happened to me several times, once with Joolz in the car during mapping!

I think it's the immobiliser playing up.

[P S K]

ukkid35 said:

Has happened to me several times, once with Joolz in the car during mapping!

I think it's the immobiliser playing up.

Immobiliser was replaced at the same time as the alarm control box. Will report back later!

[gruffalo]

mine does it sometimes, normally just after a bump so I guess it is the reed switches.

[P S K]

Quick update.

Thought the problem was solved upon finding a corroded connector on the cables from the drivers door reed switch. Made good and replaced the connector.

Sadly though this hasn't fixed it. Have checked for continuity and voltage at the relevant cables on the door / window control box plug. All seems correct. Next step is to disconnect the signal wire from the alarm control unit and see if the fault reoccurs.

That's a job for tomorrow though!

Thanks all for suggestions so far!

[RichV6]

Had similar issues with mine, but also wipers going mad and mil light. Turned out to be voltage regulator in alternator causing large voltage spikes.

[P S K]

RichV6 said:

Had similar issues with mine, but also wipers going mad and mil light. Turned out to be voltage regulator in alternator causing large voltage spikes.

Good shout. Will check tomorrow.

Thanks.

[P S K]

Just checked alternator output. Fluctating badly. Peaking at over 16 volts whereas it should be a steady 14.5 or thereabouts.

Could well be causing my issue, so needs to be sorted.

Edited by P S K on Friday 2nd August 10:06

[P S K]

Removed the alternator yesterday and took it to be tested today. It was working perfectly under test conditions, producing a steady 14.2 volts.

Removed the cable from the alternator at the big fuse to find a corroded mess! Cleaned the connections, and all is well again. Alternator is now, as it did under test, producing a steady 14.2 volts at 2000 rpm.

Have driven the car for a few miles this evening and all seems fine with the initial window problem. Time will tell!

Thanks all for your help and pointers.