Originally Posted by jorb
I don't know if you are aware that the 1954 truck offered a cup type turn signal switch assembly instead of the clamp on type.
Also there is single indicator light socket that goes between the 0 mph and the 90 mph numbers on the speedometer.
1954 was the first year that Chevrolet offered this type of turn signal for their trucks.
It is the same cup turn signal switch assembly that is used on the 53-54 Chevrolet passenger car.

Below link is the wiring diagram for the cup type turn signal switch assembly.
1954 Truck Directional Signals

Illustration
Group # 6.512 cover

Where to Find
(1954-56) Turnsignal Cup Assembly

xfiles
Wow...not meaning to hijack this post, but thanks jorb, I was recently able to locate an original turn signal cup for my 54 and the information you provided will help.

Thanks,
Phillip

Cruisin' in the Passing Lane
Former owner of a 1954 3100 w/Hydra-Matic
"To know what you know and what you do not know, that is true knowledge." - Confucius