Common problem to burn at the connector to the relay/resistor. While you're at the boneyard, might as well get the resistor AND the harness connector. Do yourself a favor and solder the connector on, don't use crimp connectors.
Another option is to bypass the relay and install an external 40amp relay They're about $5 and a couple feet of wire, a few terminals, 20 minutes time and you're done. If you need directions on how to do it, just ask.