I have a goodman furnace model # GMP075-3, serial # 9310089194
The blower fan randomly comes on even though thermostat is set on off and fan is set on auto.
1- Please tell me what should I check?
2- Please tell me where is the location of fan limit control switch and what is it look like?
Thanks
Victor

Disconnect the tstat wires from the furnace end,, be sure to tag or mark each wire so you can put them back where they came from,, do this on a warm day that the furnace isn`t needed,, watch the furnace to see if problem is still there
If the prob. Goes away you can be pretty sure its either in the tstat or a short in the tstat wires between the furnace and tstat

On the inside of cover there should be a legand type diagram ,with a list of parts and a drawn out picture telling you where to find the part