Hot blower fan lead

[Cmr446@cs.com (Cmr446@cs.com)]

   My '77 started smelling of burning plastic yesterday with the blower fan 
on. Got under the ash to find the blueconnector block gettingmelty at 
terminal 19 (heater fan circuit). The fan swich is new and I replaced the 
heatercore a few days ago. Everthing underhe rain tray looks healthy. I 
swaped out the factory ground wire for a  12ga. lead as a possible cure, but 
the terminal is still heating up. Would the ballast resistor cause this if 
it's not visibly damaged? The fan sounds strong in all speeds, but could it's 
age and wear caus it to draw excessive amperage, heating up the terminal?
Non-AC car.

Carl
77rocco
89fox