Heil 7000, exhaust fan starts, burners ignite and get up to temperature but when it is time for the blower fan to start the motor just buzzes for a while then it all shuts down. Any suggestions on getting the blower motor to work? I tried switching to cool and the blower still only buzzes without actually turning the fan.
Thanks for any suggestions.

Either a fan relay on the control board or, more likely, a run / start capacitor.
When the fan buzzes, take a stick and see if you can start the fan. Don't use your hand! If the fan tries to run, replace the capacitor.

It could also be the motor itself.