I have a 5 year old Goodman PGB024075-1A gas furnace. The LED is flashing a "2" error code, meaning an open end switch. I'm attempting to track down the potential causes of this error. After taking things apart, I found and removed an insect nest (the dirt clog kind) which had found its way into the inducer fan housing. It's all clean and the fan now spins freely. Unfortunately, same error. When I turn on the power at the service switch, with the thermostat set at AUTO/HEAT/80 deg, I can hear a click coming from the gas valve/inducer area, but then nothing. Any ideas on what to check/test next or what the problem may be? Thanks in advance for your help.

Check the rest of the vent, if it was in the inducer the only way to get there is down the vent.

I had previously removed the exterior side shields, chimney, extension and the entire vent motor. This is how I found the nest in the frist place. After cleaning it out, I was unable to see any more clog, debris, or other nests, etc. The insects most likey came in through the vent shield and made their way into the inducer fan. Everything from the flue restrictor plate forward is clean with no blockage.

Check for other safety devices in the end switch circuit. The electrical diagram should show any present. If you have a multimeter, check continuity of end switch circuit with inducer running.

I tested the end switch with the inducer on and got a reading of infinity, so no continuity.

There was another safety device. It's an auxiliary swicth attached the back of the blower and in a circuit with the rollout switch. I tested the auxiliary and rollout switches as well and they both read 0.

What do you think?

Sounds open to me. Try closing it with a jumper for testing ONLY.

I closed it with a jumper wire. Now the LED is flashing "3".

Try firing up the furnace then jumper the open end switch rather quickly. I am trying to locate the service manual for your unit.

Parts

http://igate.northernplumbing.com/partsbreakdowns/GoodmanMfg/PGB.pdf

Trying to locate service manual

Sorry for the late response, rain and travel...

OK, I was able to turn on the furnace from the service switch then jumper the end switch within about 5 seconds. I still hear the click and still get the LED "2" code.

Just to clarify; when you say "jumper the end switch", you mean, jumper the circuit that the end switch controls, NOT jumper the switch to itself... right? Peek at the circuit board for any evidence of moisture (past or present) and/or oxidation. If multi-pin connectors are present, carefully disconnect/reconnect (POWER OFF). Repeat prior run attempt.

Yes, I mean jumper the controls to bypass the switch. I didn't see any moisture or oxidation on the board and tried the disconnect/reconnect. I'm getting the same result.