2001 Saturn L-200 2.2 code P1640, P0481

[Cromy]

Had these error code PO481 for months and could not keep cleared. Service light would go out when A/C was on. If A/C off had light. Everyone said not a problem just drive it. Months of driving with light, A/C went out. Just spent hundreds replacing compressor, filter/dryer, expansion valve, fan relay module all with new. A/c cools great but I now have two service engine, service engine soon lights. The code reader says P1640 "Driver 1 input voltage high & P0481 Fan 2 control circuit. I have checked and replaced (not blown) 10 amp ingition 3 fuse, replaced Air conditioning relay with new. What else do I need to do or replace? It says on the P0481 code that when the fan control 2 feedback voltage is 4 volts or less or when fan control 2 is commanded off. What can I check? Can anyone help.

Thanks,
Cromy