Hi, have a 73 Power Wagon and I’m trying to track an electrical issue..
When I turn on the headlights the wiper motor runs. It doesn’t matter what position the ignition key is in and turning the wiper motor switch on or off has no effect on it, it continues to run.
The wipers don’t actually work, but the motor does run.

I pulled the dash and nothing looks hacked or spliced, everything looks factory from a wiring standpoint. I checked all the harness plugs at the firewall under the hood and everything is clean, nothing is corroded or burnt.

Don’t know much about the truck, got it last year on eBay and just starting to mess with it .

Any ideas on what to look at first?

Thanks in advance