Problem: Blower motor pulling to many amps and burning and melting wiring harness, pigtails, and switches.
Fix: Replace Blower motor fan with nothing but a Dealer OEM Part. Possible pigtails or new wiring harness. Add in Relays to prevent future problems from happening.
Relay Walk Through...
Relay terminal #85 - 12v Power Source from Batt.
Relay terminal #86 - low speed cut wire (from fan switch)
Relay terminal #87 - low speed cut wire (to resistor block)
Relay terminal #30 - ground (new 12 gauge wire)
Repeat this step for each fan speed wire.