I have a goodman gmp 100 4
It doesn't matter if I have the ac or furnace on it comes on goes off even when I total disconnect the thermostat I had the wires sticking from the wall the unit still came on if I place the unit on the off it still comes on but ont the furnace blower I was told that I need new circuit board is tha correct
Thanks in advance
Lee

The fan is the only thing running?

Yes the fan is the only running even when i totally disconnected the wires from the thermostat it still comes on
L

You most likely have a short in the wiring. Replacing the thermostat wiring would be the first step to trouble shoot the problem.

That has already been done but you bring up a good thing all of this started after I had the heat exchanger replaced I will look to see if any wires got nicked
Thanks L

That has already been done but you bring up a good thing all of this started after I had the heat exchanger replaced I will look to see if any wires got nicked
Thanks L