93 APV eats blower relays

My 93 APV has been having blower issues. I have replaed the resistor and the relay. It worked for a short time, then quit. I got another relay and put it in and noticed the old one was melted as well as the wiring harness. This time, I took some advice and didn't put the blower on the "High" setting at all. Two days later, the same problem. The relay is severely melted and so is the harness. What's happening?

Sounds a lot like the Blower motor is going bad and requiring more to drive the motor... There is more resistance, and this can cook the relay and the wires..

All current passes through the high speed relay contacts at all speeds: low speeds through the "normally closed" contacts (relay off) and high speed only through "normally open" contacts...that are closed when relay is ON.
At low speeds, current is limited by the resistor bank.....so if enough current passes so as to cook the relay and wires, yes the motor probably has shorted rotor windings..hence less resistance, ..unless there is an external short to ground; in either case, I would suspect the resistor bank should be paid some attention as it can be damaged as well.
http://www.avigex.ca/xport/heaterrelay.jpg

Thank you, I pulled the blower motor and noticed a couple of spots where it was rubbing against the magnets. Lots of carbon scoring around those areas. I'm going to try a new motor in it. The resistor still appears to be in good shape.