[VetteVet]

look at the steering column connector and check for 12 volts on the purple wire with the key on. Since your key switch is burnt up you probably won't have any voltage there. This is probably why the turn signals don't work. your wipers and heater fan are on the same circuit. There is a 12 gauge brown wire on the accessory terminal of the key switch that sends power to the fuse panel. this wire must have 12 voltage on it to power the turn signals.