You will need full battery power for ignition (minimum 12.5Volts although it may work down as little as 12.2Volts)
As mentioned above, it would appear that air flow is your overheating problem. It is worth pulling the heater and dismantle all air and chamber ducts. We don't have daubers here in the UK but when our 310 arrived here in the middle of winter after spending its first 25 years in Texas and LA there were dauber nests right inside the fan and surrounding ducts.
Also check that the fan is running at full speed, check for bad connections that will reduce voltage to the motor. Ensure all groundings are good.
Hope this helps.
Low or lack of power plays all sorts of tricks!
Don't take life so seriously.... it is not permanent!