Door jamb switch: how does it work

[kikkegek]

hi guys,

the door switch on my driverside does not turn on the inside lights when I open the door. Today I pulled it out and it seems OK.

now, there are two wires connected to the switch. When I hold either of them against the chassis, the inside light will turn on.

So now I am guessin, this is how the switch works:
- you open the door.
- switch makes contact with the chassis.
- inside lights turn on

I tried to clean the contacts, rubs them a little with rubbingpaper (I dont know the right word for it, I am Dutch). But it didnt help.

now the switch seems all metal.

Can you guys explain to me how this switch works. So I can check it out?

it looks like this.