I have a Trane xr80 that's about 5 yrs. Old. Everything starts (pr-fan-burner-ect.) but the blower never kicks on. I need help troubleshooting the blower circuits.

If you turn the fan to on at the thermostat will the blower come on? If yes you have a bad blower control or a bad wire connection on the heat speed off the blower. If the blower will not work in heat or cool or fan on at the thermostat, you may have a bad blower motor.