97 Blazer......turn on left turn signal, parking lights or flashers, the wipers come on. If the key is in the off position, the flashers do not cause the wipers to come on. Though maybe the turn signal switch, but the lights blew that theory. The vehicle does have an aftermarket alarm. Any suggestions?

 

Sounds like you have a short in the harness somewhere... That is a weird problem for sure. I wouldn't think that the multifunction switch would cause the issue given that it happens when the parking lights turn on...