As is good practice in all electrical troubleshooting, start at the source of power. Well, you know it is just one item, and not the whole car, so start at the fuse panel. Pay special attention to crud on fuse 13 or 16. You don't mention fuses, yet that would be the first place I would look.

Beyond that, the switches are often a corroded mess inside. The switch boots are no longer supple, and probably ripped, or even stiff enough to keep the plunger from fully extending. Was it a new door switch you installed?

With the blower motor work, you've probably seen all the grounds at the console frame and just behind it on the transmission hump. The door switches themselves provide the ground at the A and B pillars, for the dome lights.






--
Art Benstein near Baltimore

"When I read about the evils of drinking, I gave up reading." - Henny Youngman