The normal start sequence is for the thermostat to close which starts the bloer which will clear the combustion chamber and after a time-out period, the gas valve will open and the flame ignition will start to fire ( provided it is DSI, Direct Spark Ignition). The flame fires and heats a thermocouple. Two things can keep the furnace from firing at this time. The thermocouple does not get hot enough or is bad and will shut down the system. Next, the air stream from the blower has a sail-switch that has to lift enough to make the contact or the flame will not ignite.
The furnace motor is 12 VDC (volt direct current) and will generally require a minimum of about 10.8 VDC at the blower motor to run. Any lower and the blower will not get up to speed, make the sail switch and on some, the controls will not function on lower voltages.
One charged 12 volt battery should run the furnace. Check the battery for voltage and also make sure the charger circuit in the power converter is putting out 12.8 to about 13 volts. These number will vary slightly due to differnt specifications.
Also check to see if the furnace motor is well grounded.
Post which model Suburban model furnace you have and if it is the original one or not?
Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Travel with one Standard Schnauzer and one small Timneh African Gray Parrot