1948 Desoto Custom

My brake light is not working and I cannot find the brake switch. Where is it located?

Run that car by the house this afternoon about 6:00 and I’ll show you.

I’m going to take a wild guess that it’s somewhere along or in contact with the brake pedal lever.

IIRC, this model still had brake pedal arms that went directly through the floorboards, rather than being suspended from the underside of the dashboard. Is that correct?

If so, I believe that the brake light switch can only be accessed from underneath the car, i.e.–a pain in the butt to replace.

If this is the case with your car, and if you don’t have access to a lift, make sure that the car is securely supported by jack stands in addition to a good-quality floor jack when you crawl underneath the car.

Probably screwed into the master cylinder which on your car is under the floor .

I am almost certain that the brake light switch operates on hydraulic (brake fluid) pressure and screws into the master cylinder. I had a 1948 Dodge and I am almost certain this was the arrangement. The master cylinder is under the driver side floor. Pull up the floor mat and there should be an access plate so that you can top off the master cylinder. You may be able to reach the switch from there. If not, you have to get under the car.

I really liked the Chysler products of that era. My dad had a 1947 DeSoto custom. It was a great car.

Regarding the location of the stop light switch on a 1948 DeSoto, it is at the bottom of the radiator on the left side. The brake fluid line from the master cylinder spits into a “y” for the left and right wheel locations at this point and the switch screws into the top of the brass block which forms the “y”.

I have a 1948 DeSoto Custom Club Coupe that took 1st prize in the National DeSoto meet in 2003. If you have any other questions re this vehicle, I will try to provide answers.

Bob J.