My 2005 5th wheel furnace hasn't been used for several months. When I turned it on it made a weird screaming noise, after opening the outside cover and taping on things, the fan will come on, then will light and burn for about 10 seconds, the fan remains on, after about 10-15 seconds it will relight and do the same thing. It does the customary three tries, then shuts down. The red light on the board will flash. Then you have to reset and start all over, does this each time. Any help would be appreciated.