93 Astro blower motor resistor

[B.A.F.]

I have replaced the blower motor resistor 3 times in the last 18 months. I also replaced the blower motor thinking that was what was killing the resistors. The first two speeds stop working. I am using genuine AC Delco parts. There is no problem with the plug.??????????

[old_master]

Disconnect the electrical connector from the motor, check resistance on the black wire in the vehicle harness connector to battery negative.... must be less than 5 ohms. If more than 5 ohms, follow the black wire from the connector to ground. Clean and tighten the ground connection until less than 5 ohms are achieved.