2011.10.22 - Ignition Switch Repair
Having already replaced my starter (which I probably did not need to replace), alternator (which was nearing the end of its lifespan and barely keeping up) and battery (which had a bad cell) and still having an intermittent "CLICK--no start" issue, I decided that it was time to tackle the ignition switch. I wish that I had done this from the start. This is actually a very easy job (much easier than replacing the starter) and it is probably good maintenance to clean and re-grease the switch even if it doesn't fix the problem.
I loosely followed the instructions in the miata.net garage: http://www.miata.net/garage/CleaningIgnitionSwitch.html
I used CRC electrical contact cleaner and some gentle application of fine-grit sandpaper to clean the terminals and contact plates. Once everything was cleaned up, I inspected the guts of the switch and discovered that the contact terminal for the starter was worn down to a 45-degree angle on the contact edge, which is probably why I have had intermittent starting problems and why it seems to start better when I press "up" while turning the switch.
Normally this would mean that the switch is simply worn out and that it is time to buy a new switch. But since I'm a cheapskate and a tinkerer, I decided to build up a dab of silver-bearing solder on the contact brush to extend the life of the switch. To do this, I needed to use a high-wattage soldering gun (I used an old Craftsman 200-watt gun) as the contact itself acts as a heat sink, so I had to heat it up quickly and locally to get it hot enough to solder before it shed the heat and melted the surrounding plastic. I know I'm probably on borrowed time now, but I'm curious to see how well it will work and for how long.
I loosely followed the instructions in the miata.net garage: http://www.miata.net/garage/CleaningIgnitionSwitch.html
I used CRC electrical contact cleaner and some gentle application of fine-grit sandpaper to clean the terminals and contact plates. Once everything was cleaned up, I inspected the guts of the switch and discovered that the contact terminal for the starter was worn down to a 45-degree angle on the contact edge, which is probably why I have had intermittent starting problems and why it seems to start better when I press "up" while turning the switch.
Normally this would mean that the switch is simply worn out and that it is time to buy a new switch. But since I'm a cheapskate and a tinkerer, I decided to build up a dab of silver-bearing solder on the contact brush to extend the life of the switch. To do this, I needed to use a high-wattage soldering gun (I used an old Craftsman 200-watt gun) as the contact itself acts as a heat sink, so I had to heat it up quickly and locally to get it hot enough to solder before it shed the heat and melted the surrounding plastic. I know I'm probably on borrowed time now, but I'm curious to see how well it will work and for how long.