friend of mine had to replace his ignition module on Lennox unit model # G20Q3E-75-4
the original module was SP745 robert shaw
the replacement part they gave him is also Robert shaw 80-845
he said he went wire for wire but he said the blower wont shut off even disconnecting tstat, the blower stays runnin. I havent been there ...Im just throwing this out here to see if anybody knows if it could be MODULE related. I told him to check contactor to see if its stuck in. But not being there, i couldnt really say much else.