Here's The rundown, I have a suburban direct ign. heater that lights for 3 seconds then turns off. it repeats 3 times and stops. What I've done so far is, Fresh full tank of gas, replaced striker/flame sensor,thermostat , and control board. Pulled out burner and cleaned. If I supply 12 volts to the solenoid during the three seconds that It's burning it stays lit, even though the light inside is on indicating the heater is off. What am I missing???? Any help greatly appreciated!!! Thanks, Danny