First remove the switch and carefully remove the ring from the switch center post, There's a spring under the ring so don't let if fly away when you take the ring off. Snap the back off and using a thin blade, pry the contact arms from their mounting posts. Corrosion, the enemy! Scrape as much off as possible. Then using solder paste & solder coat all the formerly corroded areas with a thin coat of solder. Front & back sides of the arms and contact pads. Then solder the arms to their original posts. Don't forget the insulating spacer between the two sets of arms. Snap the back back on. Place the spring over the switch button post and push the ring back on. A touch of the solding iron to the end of the post may be required to keep the ring in place, Hold the ring down with a thin screwdriver if you need to melt the plastic. Hold it with the screwdriver until the plastic cools & hardens. Reinstall switch. Mine operates like new.
When I did mine, I used a small nail file (emery board) to clean the contacts (if corroded). Otherwise, used Q-tips and rubbing alcohol, then used a contact lube. It's held up great for 2 1/2 years so far.
They don't get hot enough to melt the solder off, right?
What would you suggest? clean off the junk, then add switch lube to it?
Won't melt the solder, but the solder will turn black and corrode very quickly without some kind of protectant on it, thus loosing it's contact, especially in an automotive environment.
All the ones I have taken apart were just crusty inside with gunk.. like ashes, dirt etc. i think they'd do pretty well as long as the car-owner keeps the car clean.
