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Lighting

Halogen Lights vs. Generator Charging

Wednesday, June 8th, 2016

With the introduction of Halogen headlights, night driving is a little safer due to more illumination. However, this improvement comes with a negative for those still using a generator for their electrical charging system.

To get the extra lighting from Halogen bulbs, the available amperage should be about 60. This will come from an alternator systems which has a charging ability of at least 75. If you are still using your original 6 or 12 volt generator, as was on most pre 1963 vehicles, the available amperage is approximately 45 at normal driving speed.

Therefore, with a generator charging system, there is not the amperage created to get the proper Halogen lighting. When at engine idle speed the lights dim much like the generator lighting systems. When at faster RPM, the advantage of Halogens is not reached.

Suggestion: Keep your original headlights when you have a 6 or 12 volt generator.

1947-55 Suburban/Canopy Express Tail Light

Monday, June 25th, 2012

What an ingenious way to keep a tail light in view! General Motors realized that with the tail gate in the lowered position the center tail light still had to be seen by the following traffic. At times the gate will stay lowered when longer freight is carried.

Therefore, the 5” round light is attached to a swing bracket. This bracket is moved by a ¼” vertical rod inside the tailgate. As the gate is lowered, the rod is moved by a hidden attachment on the edge of the body. Thus, the light is always visible!

These photos are of a 1953 Canopy Express owned by John Dunkirk of Southaven, New York.

1947-55 Suburban/Canopy Express Tail Light 1947-55 Suburban/Canopy Express Tail Light

Ignition Cylinder Light

Thursday, February 11th, 2010

ignition cylinder light

The 1955-59 Chevrolet and GMC originally came with a non-metal shield to direct light into the ignition switch to the key slot. This shield is almost always missing after fifty years. Most shrink after twenty years and fall from the switch. The accompanying photos show this snap-in shield in place. Even the die cast opening is notched on all switches to hold this non-metal plate. The illumination from the snap-in light bulb socket directs the illumination through the small lower opening, then to a hole in the switch, and finally to the key slot in the ignition cylinder. When the driver enters a 1955-1959 GM truck at night, he pulls the headlight switch and the illuminated key slot shows where to place the key.

Panel Truck Tail Light

Thursday, February 11th, 2010

With the introduction of the Advance Design panel truck in mid 1947, it was soon evident that a serious safety hazard existed with a few companies, some night deliveries required the rear double doors to be open. This prevented the taillight from being seen! No doubt this caused some accidents particularly with a fast vehicle coming from behind, with dim older bulb headlights.

The General Motors Product Service Bulletin (issued regularly to dealers) dated May 31, 1948 relates to this condition. Though it is dated over a year after initial panel truck production, it warns dealers and offers an alternative to lessen this unsafe condition.

The following is a copy of the suggested GM modification to correct the problem. As this particular product service bulletin was issued in Canada for their Canadian dealerships, it is not known if the announcement was also made to dealers in the USA .

It may be of interest that this extra light #916877 also used the same number in the Chevrolet Master Parts Catalog as the left 1939 car taillight assembly. (It appears GM used no extra tooling to create this new panel truck extra.) Note: They even requested the dealer to solder the water drain hole in this car light and re-drill because of its different mounting position.

The following is taken from the May 31st, 1948 Product Service Bulletin.

Rear Signal Lamp Released – All Panel Trucks

Some requests have been received for a signal lamp, which would be visible on Panel trucks when the rear doors are open at night. This type of lamp, which will operate in conjunction with the tail lamp, can be mounted on the roof panel, as shown in Fig. 77. The material necessary to make this installation is shown in Fig. 78.

panel truck tail light 1

Fig. 77 (above)

panel truck tail light 2

Fig. 78 (above)

panel truck tail light 3

panel truck tail light 4

Fig. 79 (above)

Of the material listed in the chart, the insulated wire, the metal plate, and the two rubber washers are to be made up locally. The dimensions for the metal plate are shown in Fig. 79 and the dimensions for the rubber washers are given in fig. 80. Assemble the bayonet connection to one end of the insulated wire and the eye terminal to the opposite end. A drain hole will be found in the side of the lamp rim. this should be plugged with solder and the same size hole drilled in the bottom of the rim for drainage.

panel truck tail light 6

Fig. 80 (above)

The installation procedure is as follows.

1. Center the metal plate, Fig. 79, nine inches from the rear drip molding over the center of the rear doors.

2. Using the plate as a template, drill two 7/32″ holes and one 3/4″ hole in the roof panel.

3. Drill a 7/16″ hole in the roof left side rail, “A” Fig. 81, and another 7/16″ hole “B” in the lower side panel behind the left rear door.

4. Place the two rubber washers over the studs in the lamp and the rubber grommet around the wiring. Assemble the metal plate on the inside of the roof panel and install the lamp using the attaching stock supplied.

5. Connect the 6 ft. of insulated wire to the plain wire in the lamp by means of the bayonet connection. Note: A two filament bulb is used in the lamp. One 3 C.P. and the other 32 C.P. The plain wire connects the 3 C.P. filament. Cut of the other wire.

6. Thread the insulated wire through the holes drilled at “A” and “B” Fig. 81. Install one of the wiring clips under one of the screws in the rear door upper striker plate “D” and the other clip under the screw at the rear of the belt strainer “C”. Compress the clips so that they fit snugly around the wire.

7. Connect the wire to the tail lamp switch “E” at the same terminal as the black tracer wire.

panel truck tail light 5

Fig. 81 (above)

1951 Tail Light Bracket

Thursday, February 11th, 2010

Beginning in 1951, the rear bumper became an option on both Chevrolet and GMC pickups. This required a change in the standard left tail light bracket. The tail light assembly was now unprotected without the bumper. GM created a new bracket design that brought the tail light slightly ahead of the rear edge of the stake pocket.

In this way the tail light was not hit when the pickup backed against a loading dock. Of course, when the truck came with the now optional rear bumper, the tail light bracket remained as earlier years.

The non rear bumper tail light bracket is not being reproduced. For the perfectionist, it will require some hunting to uncover one of these rare assemblies. Most restorers want the optional rear bumper and thus there is little demand for this forgotten bracket.

1951 tail light bracket 1

1947-1950 (above)

1951 tail light bracket 2

1951-1953 (above)

1951 tail light bracket 3

1947-1950 (above)

1951 tail light bracket 4

1951-1953 (above)

1951 tail light bracket 5

1947-1950 (above)

1947-1955 Tail Lights

Thursday, February 11th, 2010

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.

1947-1953 GMC Parklights

Thursday, February 11th, 2010

A redesigned parklight assembly was started with the introduction of the 1947 GMC advanced body style. It was placed in the front fender 3-1/2 inches below the headlight ring. A 2-5/8 inch diameter bezel held a domed glass lens to its housing by two barrel screws.

1947 gmc parklights 1

1947 gmc parklights 2

The unit was not meant to be a combination turn signal and parklight assembly and held a 3 candle power single filament 6 volt bulb. As with other car and truck parklights prior to 1968, it did not operate when the headlights were on.

This round lens and chrome ring soon found other uses. They were placed on the parklights of Chevrolets new Corvette sportscar between 1953-1962! The ring also held a different lens to the rear of certain GM cars when they had the optional backup light assembly.

1947 gmc parklights 3

1947 gmc parklights 4

During 1952-1953, GMC used an enlarged parklight assembly only different than the 1947-51 unit in size. Dimensions were increased to 3 inches diameter to give more light area. It fit in the same front fender location and the securing ring was now painted white as was most other 1952-53 GMC trim during the Korean War shortages.

This larger glass was shared with several larger GM cars as their parklight lens. The same rings, however, were chromed. These chrome rings were also used to hold a different clear lens on several GM cars for their back up lights.

Park Light Lens, Amber or Clear

Thursday, February 11th, 2010

When viewing older GM cars and trucks we see both colors of park light lenses. There seems to be no consistency that gives us the proof of what is actually correct, however, it is easy as remembering a year.

Beginning in 1963, federal regulations required park lights to show an amber color. Today, companies reproducing original clear lenses find it easy to run more in the same die using an amber additive. Therefore, in GM trucks most 1954-62 clear lenses now can be found marketed with an equivalent amber style.

One exception is the 1969-1970 Chevrolet truck. Originally it came new with clear lens but behind them are amber park light bulbs giving the required color appearance when illuminated.

6 Volt (Not Actually) Sealed Beam Bulbs

Thursday, February 11th, 2010

Two major changes occurred in 6 volt General Motors sealed beam bulbs (are actually not sealed beams) since they were first installed on vehicle assembly lines in 1940. The perfectionist restoring his truck to exact original specifications must have the correct headlights for his year. In very competitive judging, it’s these details that can make a difference. No doubt, replacement bulbs from a GM dealership with slow sales could sometimes be placed on newer vehicles a few years after the units were discontinued, however this article is based on bulbs you would have bought new from the factory during that particular year.

1940 through about 1955 – These headlights had a double filament small bulb built inside. The large glass reflector in the back was sealed from the elements.  It stayed bright even after the inside bulb burned out.  It was not like earlier open reflectors that could tarnish with age due to the silver plating.  The assembly comes with a metal black back attached for support. If the outer glass gets a rock hole, the light continues to work well. The filament is still encased in the smaller argon gas filled glass assembly (see photo).

6 volt bulb

1940 through about 1946 (above)

About 1955 and Newer (below)

The first truly  sealed beam bulb, as we know it, was introduced about 1955.  Between the reflector and the outer glass covering is the open unprotected filament (no small internal bulb). The total interior is filled with argon gas to protect the filament from air which causes instant burn out. When a rock places a small hole in the glass there is instant burn-out

One of the big visible differences in this first series sealed beam bulb and today is there are the three aiming bumps on the outside in about 1955. The bumps were necessary when using the new dealer aiming equipment.

1955 and Newer 6 volt bulb

1955 and Newer (above)

Beginning in 1955 the 6 and 12 volt sealed beams have the three glass aiming bumps molded in the edges of the lens. The bumps were needed by new light aiming equipment provided to most all dealerships. All of these GM bulbs with aiming bumps have the letters T-3 molded in the center of the glass lens. Most sold by the GM dealerships will also have the word Guide at the top of the lens.

Note: These modern bumps will interfere with properly attaching the chrome factory bezel on a 1940 headlight bucket as well if a 1937-1939 bulb light that has been converted to sealed beams. The bezels were not designed for the bulb still 15 years in the future. The 1940 GM vehicle owners will have a long hunt to find sealed beam bulbs without the three bumps.

4 Speed Back Up Light Switch

Thursday, February 11th, 2010

Four Speed Backup Light Switch – They Did Exist!

4 Speed Back Up Light Switch

The first design of the 4-speed synchronized truck transmission, introduced in 1948, was used through about 1965. About mid series, when the dealer installed backup light increased in popularity, a special switch was attached to the base of the floor shift lever. This was the only location possible as there is no external linkage on a 4-speed.

No doubt regular floor contact with shoes and boots shortened the life of this small electrical switch.

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