1988 Full Size Blazer - Have Replaced The Fuel Pump And Fuel Pump Relay. Fuel Pump Does Not Energize When Key Is Turned On. I Understand That There Is A Fuse For The Fuel Pump But Cannot Locate? Also That The Oil Pressure Switch Affects The Operation Of The Fuel Pump? Any Ideas Or Direction Would Be Greatly Appreciated ....

Oil pressure switch is a failsafe deal. Try running the starter for several seconds and see if the engine will then start with the pump running on the pressure switch. Fuse, I think, is either in the fuse box under the dash just above where the clutch pedal would be, might have a cover to remove. On the 88 I think there is a grey wire just above the heater box out under the hood, hanging out of the wire harness with a connector not connected to anything. This is a fuel pump prime wire and will send power direct to pump, try putting 12 volts to this wire and see if pump will run.

You might want to check the post I submitted in the Astro area recently. It contains a detailed description of the duel delivery system, including the contribution of the oil pressure switch. Ray

Thank you, Ray/Tom for the additional ideas. Much appreciated!