Originally Posted by FireRanger
There is no relay on the blower motor on any year ranger.
If you've already replaced the resistor pack, then either you a bad connector on the switch or resistor pack, OR the the blower speed switch is shot.
This is the blower motor wiring schematic for a 2000 Ford Ranger 4.0 =]
Look at the electrical schematic and follow the wires and see if any of them are corroded.