Unknown switch on e39 M5

[JerseyS2000]

Afternoon all.

I've recently bought a W plate e39 M5, but have no clue what the little black switch next to the ignition is for. It seems to be aftermarket so I'm thinking it might be an alarm cut-off or similar.

I'm not too keen on pressing it just to see what happens in case they've fitted a Star Trek style self-destruct system if the car falls into chavvy hands.... : )

Any ideas?

Ben

[BOR]

Is it the tyre-pressure monitor reset switch ?

[JerseyS2000]

I think thats on the left hand side of the steering wheel. This switch is immediately next to the ignition keyhole.

Thanks

Ben

[belleair302]

Is it an after market valet switch for the alarm / security system? A photo would help!

[JerseyS2000]

That was my thought but its a bit obviously sited. In my experience, those switches are generally hidden away somewhere ie glovebox.

I'll get a photo tonight

[braddersm3]

could the previous owner/dealer not shed any light on this?

[unzippy]

Eject button?

[Neil.D]

It will be the tyre pressure monitor.

You inflate the tyres to the desired pressure and hold down the button with the igntion on. Then drive for at least 10 miles and its set.