How do repair a computer module for a 92 grand prix?

The ECM is underneath the coolant reservoir on the passenger side of the engine compartment. VERY carefully unhook the wiring harness on its' side and lift it out. You can get a refurbished unit for about $80 at most parts stores. There is a small chip inside that needs to be switched over to the new module; have the guys at the store show you how. That little part costs about $160 and does NOT come with the replacement module.