When started this year it first ran the 3-4 minutes the next day it seemed to working properly now it won't start. With the lower cover on that pushes in the switch to give the furnace power you can hear the switch activated but that is all it will do. Tried fooling with thermostat seemed to make no difference acts like its not getting gas I have turned the gas switch several times and nothing sometimes when thermostat is turned you hear a slight click but nothing happens when lower cover in place one light lights up other light comes on just for a second then goes out I have checked power to the furnace it seems OK the ignitor was working when furnace was working ignitor has been replaced three times in last five years

If the door interlock is closed and a call for heat is generated by the thermostat then the ignition should glow and light off the system.