The Chevrolet and GMC left commercial taillight used during 1947-1953 is an excellent example of GM's conservative thinking towards trucks. The number one purpose for trucks was work! Therefore, if a part had been very successful on a prior body design, it just might be adapted later as a part in some new styling. Savings were in production costs and tooling. The results were still a good practical part for a working vehicle.
This type of thinking it shown in the Advance Design 1947-1953 pickup taillights. The same light assembly had not only been in use on trucks since 1940 but the red lens and chrome bezel was first used in all taillights on the 1937-38 Chevrolet passenger cars.
With the introduction of the new 1947 body style, this same six volt light continued to be used. It was now turned 180 degrees, so that the clear license light lens was at the bottom, and did not shine upward as in prior years. This allowed for a smaller taillight bracket with low mounted license plate. On earlier models the high positioned license caught the wind. This plus the use of trucks on rough terrain often caused bracket failure. With the left light illuminating the license plate, the optional right taillight did not have or need this lens opening.
Because the same lens was used on the 180 degree reversed taillight in 1947-1953, the red lens letters were now upside down. This was not a problem to GM as trucks were for utility purposes. Changing the lens tooling just to make the cast letters show upright was not a consideration. The red lens sold by authorized Chevrolet or GMC dealers normally had STOPRAY block letters at the top and either GUIDE letters in script or "STIMSONITE" in block letters at the bottom. In 1949 GM changed the red lens from glass to plastic. This thinner material reduced overall weight and gave a brighter red when light passed through. The various aftermarket lens manufacturers also followed GM's procedure. Even their lens lettering is reversed when placed on the 1947-53 trucks. It appears they also designed this lens with the 1937-1938 car in mind.
The light on the pickup and larger truck has a rectangle shape with dimensions 4 inch high x 2 1/2 inch wide. An authentic 1940-1953 GM light bucket will have the block letters GUIDE-MADE IN USA stamped on the back. These letters are not visible when attached to the factory taillight bracket. In 1947-1953 the 1/4 inch block letters STOPRAY were stamped in the top of the light bucket. These letters, prior to 1947, had been stamped in the area at the rear of the license lens on the opposite end when the bucket was reversed. In this way "STOPRAY" is always seen on the top in this series of taillight. The running light bulb (illuminating both the license and red lens) is three candle power. The stop light bulb, positioned behind the center of the lens, is 21 candle power. The bezel was chrome over the black bucket until copper shortages occurred in 1952-1953 due to the Korean War. The bezel then became black.
One minor change in this design over its early years was the reversing of a very small water drain hole in the lens retaining bezel. Engineers knew this water escape hole would be needed for drying and to drain moisture from within the bucket as the cork bezel gasket began to deteriorate within several years. This drain hole was centered in the bottom of the original light bezel; however, between 1947-1953 when the light was reversed, the bottom drain went to the lower right. This was due to an internal securing bracket welded the middle of the bezel and preventing there being a place for a center drain hole.
This taillight as used on pickup and larger trucks is mostly unprotected from the elements when located beside or under the bed. Tests quickly showed that some type of seal would be necessary in the hole where the two light wires from the bulb exited the taillight. As a modern rubber seal had not been perfected, GM skillfully came up with a solution. An approximately 2 ft. long, 5/16 inch diameter cloth woven black lacquered tube was inserted one inch into the bucket taillight wire hole. The inside end was flattened on the two wires with a heavy metal staple. This prevented the loom from being removed, protected the wires, and prevented water from entering the housing.
With the total redesign of the step bed in 1954, the six volt taillights were also changed. They became round four inch diameter units with one light bulb having two filaments of three and twenty one candle power. The lens retaining bezel was chrome plated on the more deluxe truck, painted black like the bucket on the standard models. The clear license lens was in the bottom of this bucket to illuminate the plate below. With the optional rear bumper on pickups, the license plate moved to the middle of the truck and the taillight did not have the lower lens window. As before, the right light was an option.
The 1947-55 taillights on the panel truck, suburban, and canopy express (single unit bodies) had no similarity to those on the pickup and big trucks. On panel trucks a single light was placed near the center of the left "barn door". The lens retaining bezel was chrome with dimensions of 3 inch high by 4 1/2 inches wide. A decorative stainless two inch wide strip on top of the housing has the stamped letters GUIDE R17 T. A single socket in the housing holds a double filament bulb of 3 and 21 candle power. The license plate bracket is secured to the rear of the bucket and allows illumination of the tag below the light. During these Advance Design years, this panel truck lens and chrome bezel were also used on the rear fender of the Harley Davidson motorcycle.
The canopy express and suburban bodies also displayed a single taillight with suspended lower license. It was attached to a cast metal swing bracket on the center of the tailgate. This bracket plus a special vertical connecting rod made up an ingenious design. When the tailgate was opened to its horizontal position, the taillight and license would swing 90 degrees so that it could still be seen by the following traffic. This round taillight was normally black with a 4 3/4 inch diameter chrome lens retaining bezel. Inside are two sockets holding individual bulbs of 3 and 21 candle power. Block letters on top state GUIDCOLITE STANDARD. To save costs GM adapted this light from a prior application. It had been the GMC pickup taillight from the late 30's through 1946. During these Advance Design truck years the light was also found on General Motors station wagons through 1952.
As the 1950's progressed, there were increasing requests for a right tail light. This was a GM dealer installed option to be placed on new or pre-owned vehicles. On pickups it was easy! The option included a right side light and bracket closely matching the standard left assembly.
Adding a turn single option today 1947-1955 single unit body created problems for GM designers. Neither the single factory taillight on the double door or the center unit on the tail gate were in a good position to be matched with a second live assembly. GM solved this by offering a turn signal kit containing two matched taillights. These were dealer installed beside the vehicle belt line near the doors and above the edge of the tailgate. These small bullet shaped lights were actually from a 1939 Chevrolet passenger car. It appears GM dusted off the ten year old car taillight tooling and kept expenses on this option to a minimum. The letters "DURAY" are stamped in the top of the painted housing. The chrome bezel retains a 2 5/8 inch diameter red glass lens. Due to a small water drain hole, there is a right and left on these turn signal lights.
NOTE: It is interesting that both the pickup truck and the tailgate lights, each developed during the late 1930's, continued with separate bulbs and sockets for each filament. The door mounted oval panel truck light, introduced in mid 1947, was provided with a more modern double filament bulb in one socket.
