blower/ fan control switch stopped working. no fuses listed. What to check for?

thank you for prompt reply; there is no fuse or fuse-link etc for blower fan then, that's what I needed to know. the connector-plug and attached wiring show weather cracking, but 0 ohms resistance [re-taped]. and one 'on line' source says; relays and resister are by-passed when fan is at full speed. checking them out any way. then R&R switch and testing for wiring short.