I ripped apart and tested the Jetta's driver's side lock module last night and the door open/closed switch still sounds fine and clicks nicely when you actuate it by hand, but alas the multimeter tells a much different story... 24 ohms when closed. Obviously it's toast. The one for the lock and two key turning ones (the Cherry ones) are all in perfect shape and very close to 0 ohms when closed (as they should be). I'm assuming the passenger side is the same, minus the ones for the key turning of course.
I have been trying literally all day to sort out a preferably local, and if not, Canadian supplier for 2x V4NSUL. I found out that Grainger (Acklands-Grainger in Canada) is supposedly a Saia-Burgess distributor, so I gave a local store a call, and they didn't want to deal with me unless I was a business or a farmer. I said for the purposes of finding out whether you sell them or not, and they couldn't find the part number. I called Active Electronics here in Winnipeg and they have never heard of Saia-Burgess. Active sells a Mode electronics switch (47-300) that's very similar and would work, but it's not sealed like the V4NSUL so I don't know for how long. Would smearing some di electric grease or something in there help it? They're only $3-$4 so I think I'm gonna go with that one. Hopefully they've got stock.
The magnetic switch... It's actually a fantastic idea! I'd love to see it done because there are no moving parts to get worn out and it would (hopefully) just work. I did a quick search on Mode's website, and came up with this:
http://mode-elec.com/pdf/switches/47-600.pdf. These are the same exact switches that your house alarm system uses to determine whether or not your doors are open, so why not in a car? They sell at Active for under $7, so very cost effective. All you would have to do is run the wires from the normally open (I think...) and common to the same locations on the lock switch circuit board, bypassing the existing microswitch. The other side is just a magnet, so you can glue, rivet, bolt, or otherwise attach the piece somewhere where it won't get kicked. The other side obviously needs to stay on the door.
The datasheet says the max amperage is 250mA (or 0.25A). Anyone know what kind of amps go through this switch? Also the stated operating temp is between -20°C and 55°C which doesn't quite cut it with our friendly Manitoba winters. At the back door of our house, the two halves are about 1/4" to 1/2" apart and the alarm thinks the door is closed. We had a fairly bad draft right where the mag switch was for a couple years and when it was -40°C it still worked... YMMV I guess. You would have to experiment with the multimeter with the parts you had in your hands to see exactly what their spacing tolerance was though. I think this would be dead easy to do. You could even paint the switches body colour, or hide them under trim or whatever, just keep the wired half of the switch away from the speaker or you'll have the same problem as now: The door will still think it's always shut heh.
Anyway, there's some food for thought. To me, a magnetic system would be far more reliable due to the lack of moving parts (providing it works at the temperature extremes we have here in Manitoba), but would involve a tiny bit of hacking and good placement of the halves to get it to work just right. These things stand up to house doors being slammed, so I think they would be fine on a car door.
I just might kludge this together and try this... I'll keep you updated on the progress and if it works I'll write up a quick and easy how-to, leaving out all the stuff that's already covered in other how-to's of course. No need to repeat ourselves.
Cam