My Coleman 7956A856 heater wnot come on. The A/c works OK and the heater worked just fine last year. Anyone have any suggestions?

We are going to need a lot more info to help. What exactly does the furnace do when calling for heat? Take the covers off the furnace, have somebody turn the thermostat up, and watch and listen and then tell us exactly what you see and hear. Do you have a standing pilot, or hot surface igniter? Just to many things that it could be for us to help without more info(and lots of it). Good luck, hope we can help. Lee.

Ps, best bet would be to call in a furnace tech to solve the problem.