The central lock system has been acting up - as soon as I put in fuse #8, the three non-driver doors lock. The key won't turn to the unlock position, and the stalk will not go down.

I pulled the wrap-around switch, and it's all corroded on the metal contact strips, so I'm looking for a replacement. But I am puzzled - I can't see how the thing works.

I'm looking at the assembly, and I see the stalk/wiring harness. One end of the harness plugs into a three prong female plug in the door. On the male end, the three wires split to three pairs. Three of the six wires run into a plastic sleeve that surronds the stalk, and three run to the wraparound switch that girdles the door lock cylinder. So far so good.

First problem - there is no play at all in the stalk. I would think that the stalk has to move inside the round plastic sleeve where the wires are in order to activate the switching. But there is no movement at all.

Now would be a good time to mention that the system worked perfectly until about a month ago.

So, first, I can't see how the plunger mechanism operates what must be a switch inside that plastic sleeve.

The second problem is that I can't see how the wraparound switch works. There are two pieces to the switch. One is at the end of the wire harness, is semicircular and has three metal contacts that match to the three wires. The second is also semicircular, and snaps into the harness end, and this is the piece that fits around the lock cylinder. However, this inside piece completely covers the metal contacts, and I cannot figure out how turning the lock cylinder causes any contact to be made to trip the relay.

What am I missing?