On my 1998 Honda when I activate my heating cooling system. The only fan speed that works is the fourth position, High speed. When 1 through 3 are selected the AC pump turns on, but no fan. Please let me know which relay or part I need to replace.

Heater Fan Switch. Disconnect the negative battery cable; then, remove and clean the 6-P connector, before replacing switch. Spray switch with electrical contact spray. This switch should last for many years.