RV Repair: suburban heater electric and LP, lp side, hot air

Question
My heater worked for the past 4yrs. I turned the heater on and it just blows out cold air, I'm not really sure which button should be on for electrical, red or green,

Answer
Leonard. I am guessing this but is this in a Alfa? If so then it has a basement air and that is what gives you the electric side. The LP side is strictly for the furnace as they all run on LP. If it is coming on and not blowing hot air then it could be a couple of things but more than likely it is the igniter board. Depending on what model suburban you have will depend on how you will want to pull it to test it and repair. Let me know a model and I can help more. Thanks, Bill