Steering lock/ignition switch

[Dave Plowman (News)]

The ignition switch on my BMW has a number of interlocks - nanny state rules.

One is you can't remove the key without putting the car in neutral or park.

Just recently, on a couple of occasions, I've not been able to remove the key. Both times when shopping - so not (obviously) wanting to leave the car with the keys in it, drove home. Where the key then came out normally.

Basically it's not turning to the fully off position. But I'm not sure what's stopping it - my guess is the interlock from the gearlever. Anyone had this sort of system apart and know how it works? A complete new lock and switch assembly likely costs as much as a new car - by the time it's been programmed in. ;-)

It's quite easy to remove the actual lock barrel itself - if I knew what to look for inside.

[newshound]

There seem to be two possibilities (assuming it is related to the gearlever interlock). Either the "switch" at the gearlever end is giving a false (in-gear) signal and that is "correctly" engaging a mechanical anti-withdrawal lock, perhaps by a solenoid. Or the gearlever end is OK but the "solenoid" is sticky and so not freeing up mechanically to release the key.

Knowing that locks get sticky and sometimes need jiggling to release the key even without such interlocks, I'd think mechanical is more likely. They way I would tackle it (YMMV)is to squirt in WD40 and jiggle. If that frees it up, you know this is where the problem is.

If you can identify the electrical signal wire from the gearlever to the ignition, you could check its state as you jiggle the lever (with the ignition on, perhaps with the engine running too). That might show you if the gearlever "switch" is behaving anomalously.

I'm assuming it's an analogue signal, maybe a dangerous assumption in these times. If it is digital, it's going to be more difficult!

[Michael Kilpatrick]

If you put your ear to the key, can you actually hear anything clicking when you move the gear lever? Is there a small solenoid for the interlock?

Michael

[DerbyBorn]

Michael Kilpatrick wrote in news: [e-mail]:

Is there a sequence issue? Perhaps sometimes you try to turn off before getting the gear lever to neutral and this puts a mechanical load onto the release mechanism.

[Dave Plowman (News)]

I've had the car for 12 years.

[Scott M]

The early interlocked boxes used a cable from gear selector to switch I vaguely recall from my old E36 Bentley manual. Whether the E39 copied this I don't know. My 325 didn't have such nonsense thankfully so I never investigated it.

I hope I'm not teaching you to suck eggs (ie I can't believe you haven't come across these!) but have a shufti at:

- online parts catalogue (very useful)

tis.spaghetticoder.org - tech info (if it's mechanical, try here)

wds.spaghetticoder.org - wiring diagrams (if it's electronic, it'll be in here)

Scott

[SteveW]

If you do find that it's a mechanical interlock, don't fix it - just remove the stupid thing!

Manufacturers do seem to come up with some odd ideas - I had a car that locked the boot when the engine was running and would not allow either the internal or external release switches to open it. Now I can understand that they designed it to lock so that no-one could grab stuff from your boot at traffic lights and I can understand not accidentally opening the boot from the internal release while moving, but why not simply make the internal button enable the external one for 5 seconds or something like that so that when picking up or dropping off a passenger, it's not necessary to switch the engine off while they put their stuff in the boot?

SteveW