OK, figured this much out. There is a bracket that is supposed to hold the thermo switch to the heater bottle. The round indentation I showed on the reservior bottle is where the heater element mounts. It's item # 25 in the picture. Thinking this over, I gotta wonder why the squirter needed a volatge connectoion in the first place. Tomorrow morning, I'm gonna see if the squirter works, without the original harness. It's still getting voltage from the fuse box to the reservior pump.