I would continue to seek the correct fix. In the meantime if you are adamant about wiring a switch up, here is how I would do it. Get yourself a SPDT 30 relay. Like one of these
http://www.parts-express.com/wizards...ter=spdt+relay
Get the socket for it too.
http://www.parts-express.com/pe/show...TOKEN=10952241
An inline fuse holder like this
http://www.parts-express.com/pe/show...TOKEN=10952241
Then a basic toggle switch or rocker switch.
http://www.parts-express.com/wizards...switch+lighted
You may be able to get these parts locally but, this is the cheapest place I know. Ask parts express for a relay wiring diagram also if, you order from them. Even if you don't have the wiring diagram we can help you get it wired up no problem.
Once again, I'd look further into what is causing your problems and not just relying on a work around