Door sensors and welcome lights

[z0mb13k1ll]

the door sensors on my 07 sedan don't work(with the exception of the back left door sometimes) they appear to have some rust inside the sensor. I also noticed they have only 1 wire, is it running through the frame as well?
Is there a way of repairing them or a place where I can find new ones for cheap?

Also i bought some welcome lights to install under the doors, is there any wiring i could tie into inside the doors for these or would i have to run a wire from somewhere to trigger them?

http://i.imgur.com/giOTkt6.jpg

http://i.imgur.com/e1Uca6M.jpg

[CTScott]

You could try some electrical contact cleaner. They are a very simple switch which ground to the chassis when the door is open. That's why there is only one wire.