Is the switch position marked not used in the attached picture always hot or switched on with the key?
It is switched on with the key.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
There should be one that's connected to the coil with the key on or it won't fire the spark plugs.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
The ignition switch in my '52 GMC (I don't know if it is original equipment, but it is the original type switch as shown in Darren's picture above) connects power to one terminal (I call it accessory) just a few degrees of key turn before it connects power to the other terminal (call it run). I don't know if the switches are all like that, but I use it to my advantage by connecting the radio and the turn signals (including the 4 way hazard lights) to the accessory terminal and everything else to the run terminal. With a gentle turn of the key I can power up the radio or 4 way flashers without powering up the rest of the truck.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
I have an after-market switch in my 54 but no accessory position, it is there but does not work. Unfortunately, the guy that did the most work on it retired.
Ron, The Computer Greek I love therefore I am. 1954 3100 Chevy truck In the Gallery 2017 Buick Encore See more pix 1960 MGA Roadster Sold 7/18/2017
The original switch in a ‘50 Chevy has only two positions, on and off. One terminal supplies the power and the other two are both hot when the switch is turned on. One as Kevin said, goes to the coil and also to the Amp meter. The other goes to the regulator.
This picture is the wiring diagram for a 50-51 from a 1948-1953 Chevrolet Shop Manual. I highlighted the paths to make it easier to see.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
Phil a slight correction. The hot wire comes FROM the amp meter. The other one in the diagram goes to the coil and the gas gauge. If the coil and amp gauge were connected, the ignition would be hot all the time and you couldn't turn the engine off. The one that shows nothing connected could be used for accessories, like radio and/or heater fan.
It wouldn't be the first time that someone got off track on that hard to follow wiring diagram. I've been puzzling over it currently as I'm working on some repairs to my wiring harness.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
