I have a goodman GMNT080-4 that will not light. The inducer motor will turn on and run for a while then I will get 3 blinking lights on the board. Using a multimeter I found I don't get a change in voltage on my pressure sensor switch, and I also do not get a zero omhs reading on the leads of the switch. Does this mean I have a bad switch? I have made sure the lines all clear and have cleaned the nipple as well. I have found that if I disconnect my exhaust from the my inducer motor I can get my furnace to fire up. I'm at a loss here. I'm not too familiar with furnaces just been spending a lot of time on Google.

My York/Luxaire gas furnace PCMU-L016N095B does not fire up. The problem seems to be that the "hot surface ignitor" is not getting powered up. I checked it for conductivity and got around 120 Ohms on it when cold. Unplugging the ignitor and attaching the multi-meter I can't detect any voltage during the call for heat cycle. Upon initiating the call for heat cycle, the blower runs first, then after a while I can hear the gas flowing, but the ignitor does not start to glow and the gas shuts down. However at this point if I light the flames by hand with a lighter torch I can get the furnace to heat for a while. Is this a case of a broken circuit board or is there another step that could prevent the ignitor from getting powered up? What could be the problem? Is there anything additional I could test? Thanks ps. The ignitor was already replaced one time 3 years ago by a hvac repairman. Its a flat 271N 02532625 type.