I don’t know how to do this. How do I find an unswitched power source outside the wiring harness? I have identified from posts here a switched source, tach wire for the dimmer circuit, common ground... there is a red wire that powers something running through the windshield wiper mechanism area. It’s a mystery if that is a proper source. Who can assist.

Wire from battery fuse to somewhere close to the windshield wipers

 

Unswitched (always on) power is available under the hood at the fuse box. It's the large gauge red wire at the left rear of the fuse box.