A/C Blower Fan Issue

[gramps77]

Originally Posted by gchemist

The circuit for resistor is faulty. The resistor is directly above the relay. The resistor bolts into the evaporator box. Check it for broken springs or connections.

This didnt make sense until I went back out to the truck. THEN, found the blue wire going into the relay apparently shorted enough to melt all around the plug where its at. The blades on the relay look rough and are obviously the originals. There are arc burn scars at the plug to relay.
Could this simply be from all the buildup and years of sitting outside caused a bad connection? Wondering if I should just swap the relay and get the new harness TUCSONJWT mentioned.