@jason-hartmann Jason, I would suspect the stop light switch first. If it is the hydraulic type, they are available at most any local auto parts store. Standard brand SLS 24 is the one with screw terminals, that I see on my old Chevys.

It sells for $20.00 or less. You can often find old stock ones on eBay for less if you are not in a hurry. Good luck.

Mike

 The 48 will have the brake switch activated by the brake pedal arm, switch is on the firewall. I would start with checking for power at one of the wires, key doesn’t have to be on. If you have power then jump the to wires together and if the lights work you need a switch. Right now I don’t remember if the power comes off the ignition switch or off the headlight switch to go to the brake light switch.

As Dennis mentioned, the 1948 has the mechanical lever type switch while 1941 is hydraulic.  Power comes from the back of the headlight switch and should be hot to the brake light switch all the times even if it goes through an optional signal light switch.  The original headlight switch has a common fuse on the back for the brake light circuit, as well as the dome and glove box lights.  If the dome and glove box lights are not working you could have a blown fuse.  Mike

I wanted to leave a follow-up in case someone else comes across this question.  I checked the brake light switch as recommended, and found the hot wire from the headlight switch was broken at the connector to the brake light switch.  When I have time, I'll fix that wire and I should have brake lights again.    Thanks for the help to everyone who replied!

@jason-hartmann Glad you got it figured out. Electrical gremlins can be a real hassle.