Blower motor works sometimes and sometimes not. When it works, it works on all settings. When it doesn't work, it won't work on any settings.

Replaced blower motor resistor a while back. Motor seemed to work fine for a while, then back to same sporadic problem.

Took blower motor out and connected to battery. Works fine.

I know where the relays are, but not sure this is the problem.

Anyone have a wiring diagram and/or diagnostic procedure??