I got a 97 lumina 3.1 and behind the pass side headlight there is a electrical plug that runs into the wiring harness. Not sure if this is a block heater or not. I checked the RPO codes I thought it was 8U4 for the block heater but I didnt see it. This car also came from wisconsin so im sure it seen alot of cold weather.

8U4 is a GM block heater option code, but not for the 97 Lumina. The RPO for the Lumina's engine bolck heater is K05. I would bet that's what the plug you're seeing is for.

Cool thanks a lot if someone has a lumina with a block heater maybe they will chime in.