Blower Motor Mistery

The blower motor use to work on the lower power settings, but when it went to high it would usually shut off, but eventually cycle on and off by itself. I replaced the switch assembly (junk yard), then the blower motor (it work great for a month) then the gremlin came back. I replaced the resister and nothing different. now a week later I have no blower motor?????

What year and model? Manual HVAC or Automatic Climate Control? The older ones used a separate resistor and high blower relay, on the newer ones the relay is part of the resistor assembly.

Check blower motor ground connection to the body.

With the key on, and the blower switch in high speed position: both orange wires at the relay and resistor must show battery voltage.

Post your results.