Just trace the wire. My car had a button that when pressed made a noise in the engine compartment. Turned out to be an auxiliary oil pump but the pump was gone and only the motor was back there. My other switch is a toggle for the Andial fuel enrichment system but you would never know unless you traced the wires.

So my advice is to trace it and forget asking people. How would anyone know?

I asked under the assumption that some other 930's may be equipped with the same switch.

I had installed a similar switch on my '87, but it was on the dash.

It was an override for the oil cooler fan in the front wheel well.

If I was sitting in traffic in the summer I could flip it on and watch the oil temp go down in a couple of minutes.

Look at this thread:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/802797-wastegate-boost-controler-question.html

there could be your answer.

Ah, I guess I was right when I assumed it was connected to my boost controller.

Its for the alpine alarm.