As with many other items on the Advance Design Series trucks, there were also changes in the ignition switches. Both Chevrolet and GMC shared there several switch changes during the sever year series.
In the beginning (1947-1948) a unique three position ignition cylinder and housing was introduced. This was a first for GM trucks. It related to a country with limited crime and a time when many people did not lock their houses. The switch allowed the truck to be started without a key.
By turning the cylinder and key to the far left, the ignition switch was locked. However, the middle position was the big difference! Here the ignition was still off but a small tab or teardrop extending down from the cylinder face allowed the driver an option. With a touch of a finger you could turn the cylinder to the far right with or without a key due to the teardrop.
This was a convenient feature for many owners, particularly on the farm. No longer did they worry about losing the key or having to dig when it was in a pocket. They simply moved the tab from the center to the far right and the ignition was on. A security feature was built in. The ignition could not be locked without the key, so there was no worry about it accidentally being moved to the lock position.
This three position switch, also used on the 1947 Chevrolet car, was discontinued about the end of 1950. GM then returned to the two position on-off cylinder and housing that would not work without a key.
Between 1947-1953 the switch and cylinder combination plus a one candle power bulb and socket was attached to a sheet metal housing. This assembly is screwed to the top of the lower dash lip out of sight. Only the round key cylinder face is seen by the driver. It extends through a larger hole in the dash. A resulting 1-1/16 inch circle opening between the dash and this cylinder face produces a lighted ring at night from the adjacent small bulb. This allows the driver to easily locate the switch in the dark.
In 1954, with the total redesigned dash, there was a complete change in the ignition switch. The threaded end of a die cast housing is held in the dash by a chrome lock ring. Only this ring and the key cylinder face is visible to the passengers. It is also the two position on-off type.
With the introduction of hydramatic transmission during these years the switches did not change. The starter motor was activated by a button near the headlight switch not by the ignition switch.
1954 Ignition Switch (above)
1954 Ignition Switch Rear View (above)