The Stovebolt Site Forums The Parking Lot Panels 'N Burbs Suburban rear lights

I think that dual rear lamps were required by law in a few states during Advance-Design years (I think that Washington state is/was one example).

That is one reason why GM provided the Panel-body dual tail lamp accessory in all Advance-Design years (it was an easy matter to mount a second tail lamp on other trucks). In 1954, the dual lamp (front and rear) directional-signal package became available as a GM accessory on all Chevrolet trucks (the wiring diagram/routing for Panel-body trucks is given at the link at the post above).

I have two 1954/55 GM trucks (that coincidentally came from WA) that had factory directional signals with original wiring run along the frame, under the body. The signal systems worked fine after 50+ years (Note: plastic-coated wire came into use in 1954 - I doubt if the cloth-coated wiring would have lasted that long). The plastic coating was quite brittle and when I removed them they broke/cracked all over the place on the wires that ran to the rear lamps.