VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 1948 Ignition Switch Wiring

I'm looking for a wiring diagram (or an explanation) of how the 1948 ignition switch is wired. In 1948 they came out with a 3 position switch so you could take the key out in one of the positions and still let someone start the car without giving them your key. All fine and good, but the shop manual (which looks like a reprint of the 1942 manual really) only shows a 2 wire ignition switch from what I can tell. For the 2-wire hook up, it looks like one wire on the ignition switch is a hot wire fed from the ammeter and the other contact has wires that go to the ignition coil and gas guage. What do I do with the third position on the 1948 switch? Thanks!

I sent you the wiring diagram for a 1949. Sure the ign. is wired the same. Shows the third terminal open.

I have 3 shop manuals for my '48. They are word for word and number for number like the '42 shop manual. I recommend the service bulletin reprints from Chevy Acres for your '48. I have the reprints for '46 to '49 and I learned a lot of vital info from them. An example: Sometime in the '48 model year the polarity reversing switch was no longer factory installed. That required a change in the distributor - only one terminal on the later distributor housing instead of two and different points, too...

Thanks. Did you find anything about the ignition switch wiring in there? I took a look at the material I had and didn't come up with anything except that there was a change for 1948. No details on if it affected the wiring harness connections. As soon as I get my ignition switch keyed so I can actually turn it to both positions, I'll see if they both complete the same circuit and the additional connection on the back is just for additional add-on wiring.

The late 1948 distributor had a larger breaker plate ( plate went all the way out to the dist. housing0 - no insulator required) and used a different set of points The 1934-1940 and late 1948 and up points were the same. The 1941 - early 1948 were different and smaller.
The change was made in March of 1948.
The reversing switch, like the 10 MM spark plugs, were always a sore spot on the cars so equipped. The other litte problem was with the spring type link for the acellerator pump in the carburetor in 1947 and 1948. Like the reversing switch, Chevrolet said not to remove it, and by 1949 they were all history. The vacuum gear shift kind of fell into that catagory also.....although I did like it for normal driving.

Thanks, Gene. Yes, my car is a late 48 car - it was built in September 1948 - so I have the late, single connection distributor and thankfully not the reversing switch set-up. I'd hate to have to put that on just to be correct for the month the car was built in, but luckily the VCCA isn't that picky, so even if it was an early '48 car it wouldn't be on mine.