gmp100-3 furnance won't try to ignite
follow the wires from the ignitor that lead to the control box.
my control box had about 6 or 8 wires coming off of it, going to the ignitor, the blower, and goodness knows where else.
shut off power to the furnace, and then, while you are looking at the control box, turn the power back on. you may see a red LED turn on briefly and go out, which is supposed to indicate that the electrical wiring is OK. if it stays on, that is supposed to mean the control box is bad, and if it blinks that means the control box thinks something external to itself is mis-wired.
when I turn on the power, my control box blinks once. if the thermostat is set to heat, I can hear some clicking in the furnace, then I see the bright orange glow of the ignitor, then I can hear a low woosh of gas, and then the flames start and the ignitor goes off.
I just did internet search for the manufacturers of each component. The control box led me to a troubleshooting flowchart in a PDF file.