Ever since I got the Impala I struggled getting all the taillights and signals working properly. The taillights didn’t ground, the turn signals didn’t cancel and the blinkers wouldn’t engage. I replaced the cancel pawl behind the steering wheel, replaced the steering wheel, cleaned the taillight buckets, and tried unsuccessfully replacing the turn signal switch that I found nearly impossible to install , but thought a couple weeks ago I had everything figured out. This weekend we were a show at the Gilmore Museum here with all of our cars and the trailer, and my wife said, “The left brake light on the Impala doesn’t work.” AAAARRRGGGHHH. I had just finished replacing the entire steering column, steering wheel on our ‘52 DeSoto wagon to fix the worn out tern signal switch in it, and now the Impala was exhibiting the same issue. Whenever either turn signal was turned on, the sides brake light was out, until the other side was engaged, leaving us with brake lights on only one side or the other. Having had our Pontiac wagon rear ended, I am super focused on having ALL light working and bright all the time. This afternoon when we got home I tore into it (Impala) and replaced the turn signal switch at the bottom of the steering column. After an hour and a half playing contortionist under the dash it’s finally fixed. I got the new switch mounted and adjusted properly, although it was impossible to get both the mounting screw is wit the column in the car. One will do. I had a hip replacement a year ago and until now I simply couldn’t get under the dash to replace that switch. The brake lights and signals work each time, every time, I replaced a busted taillight socket that wouldn’t ground, I’m calling it good.
Rube Goldberg would be proud of that switch system! I busted the turn signal switch on my 62 Vette a few days ago. It's the 1953 switch design, which has a fatal flaw that shows up after a few decades--the pot metal housing gets egg shaped, and won't stay clamped, and the actuator can't move as far as it should. But I'll get it going again, too. Having all the lights back there on old cars is indeed important.
63 years on, I would have to say that the factory system, with a “monkey-motion “ rocker lever behind the steering wheel, a Bourdon cable to an impossible to access switch 2 feet down the steering column, that yes, that’s terrible way to have done it. Rube Goldberg would LOVE it though.
I don't know if your Impala might have a tilt column, but if it does, make sure you check it in all the tilt positions, since the cable moves when you tilt it. I recently installed led tail lights in a '57 Corvrtte to address the bad socket problem. These were the ones that go in place of the stock lense. The socket is no longer used then. Plus, they're much brighter. Love your wagon.