[cjsevert]

Goodman GMPN 120-5 Gas Furnace-------------Turn furnace on and exhaust vent motor comes on for milliseconds to begin to turn (only a couple degrees of rotation). I can hear a hum, then, which may not to be coming from motor---not apparent to touch. With a Digital Voltmeter on input (Black to White) leads, I see some power coming on momentarily but immediately falling to zero---can't read meter to see how high the voltage is since that input power turns off so fast. I suspect that the exhaust motor is not the problem---it turns very easily with a screwdriver touch to the motor coolant fan blade. I have disconnected output hose to outside vent in my troubleshooting. What could cause this problem?

[dken7]

If your inducer motor is dropping out like that, it sounds like it is not proving flue. Check for restriction in exhaust pipe of furnace. Check flue switch. I hope this was helpful.