HVAC blower works intermittently hj-60

[Ricktor]

Any ideas on why my HVAC blower would work when the weather is warm and not when it's cold? Heat and AC work fine it's just the blower. 89 HJ-60

 

[Output Shaft]

28 year old electric motor. Things contract & expand with temperature.

 

[doug720]

When operating the fan speed control, do only certain speed settings work? Sometimes only low and high speed settings work, but the mid settings do not?

If so, that can be heater relay, or a bad switch.