I pulled the actuator, still connected to the harness, and had a friend switch from 4HI to 2HI. It stayed extended. I could move it by hand, so it’s not jammed. Considering the age of the truck, it’s cheap insurance to replace it. Amazon has them for $42, new replacement harness for $50, and the push button controller for $42. Ordered all three.
When I got the existing switch to work, the lights constantly flashed when 4HI or 4LO was selected and was solid in 2HI. I’m hoping that with the new switch I’ll get 4LO back.
I’ll keep you posted