Tail Light Assembly

This procedure covers removal and replacement of the tail light assembly on a 1972 Ford F-100, including lens, housing, bulbs, and gasket inspection.

Warnings

Tools required

Parts

• Tail light lens × 1 — Use OEM specification or aftermarket equivalent
• Tail light housing gasket × 1 — Use OEM specification
• 1157 dual-filament bulb (stop/tail) × 1 — 1157
• 1156 single-filament bulb (turn signal) × 1 — 1156
• 97 single-filament bulb (license plate, if applicable) × 2 — 97

Preparation

1. Park the vehicle on level ground and set the parking brake
2. Turn off all lights and remove the ignition key
3. Open the tailgate for better access to the tail light assemblies
4. Determine which side (driver or passenger) requires service

Procedure

1. 1

   Remove tail light lens
   From the exterior of the vehicle, locate the 4 Phillips head screws securing the tail light lens to the housing. Remove all 4 screws and carefully pull the lens straight back away from the housing. If the lens is stuck due to old gasket material or corrosion, gently work a flathead screwdriver around the perimeter to break the seal, taking care not to crack the lens.
2. 2

   Inspect and remove bulbs
   With the lens removed, you will see the bulb sockets inserted into the housing. The 1972 F-100 typically uses a 1157 dual-filament bulb per side that combines the tail, stop, and turn signal functions. Verify your specific tail lamp design, as some configurations may use additional bulbs. Press each bulb into its socket while turning counterclockwise approximately 1/4 turn to release it from the bayonet mount. Pull the bulb straight out. Inspect each bulb for blackening or broken filaments and replace as needed. Verified detail (The license plate bulb designation (97) is unverified for the 1972 F-100; license plate illumination on this era commonly used bulbs such as the 1155, 67, or 631. This should be confirmed against factory documentation.): License plate bulb (verify correct bulb number against factory specification, if applicable)
3. 3

   Remove tail light housing (if necessary)
   If replacing the entire housing or gasket, access the mounting hardware from inside the bed. Remove the nuts securing the housing studs to the bed panel using an appropriately sized socket (verify count and size for your configuration). On some configurations, there may be speed nuts or sheet metal screws instead of studs and nuts. Once fasteners are removed, pull the housing straight out from the exterior of the vehicle. Verified detail (1/4 inch socket refers to socket drive size, not fastener size. The actual nut size (likely 5/16", 3/8", or 7/16") should be specified for the 1972 F-100 tail light housing mounting nuts.): Remove the nuts securing the housing studs to the bed panel using an appropriate socket (typically 5/16" or 3/8").
4. 4

   Clean mounting surfaces
   Use a wire brush or sandpaper to clean the mounting surface on the bed panel where the housing gasket seats. Remove old gasket material, corrosion, and dirt to ensure a proper seal. Clean the back of the housing and the bulb socket contacts with electrical contact cleaner and a shop towel. Inspect the housing for cracks or damage.
5. 5

   Inspect wiring and sockets
   Examine the wire pigtail and bulb sockets for corrosion, melted plastic, or damaged terminals. The sockets should have firm contact springs and no signs of overheating. If corrosion is present on the socket terminals, clean with electrical contact cleaner and a small wire brush. Apply a small amount of dielectric grease to the socket contacts to prevent future corrosion.
6. 6

   Install new housing gasket
   Position the new gasket onto the back of the tail light housing, aligning it with the mounting studs or screw holes. The gasket should sit flat against the housing flange. Some gaskets are adhesive-backed; if yours is not, the compression from mounting will hold it in place.
7. 7

   Reinstall tail light housing
   From the exterior of the vehicle, align the housing with the mounting holes in the bed panel and press it firmly into place. Ensure the wiring harness is not pinched or stretched. From inside the bed, install the mounting nuts and tighten evenly by hand, then snug with an appropriate socket (typically 5/16" or 3/8"). Do not overtighten, as this can crack the housing or distort the gasket seal.
8. 8

   Install bulbs
   Insert the appropriate bulbs into their designated sockets. The 1157 bulb (with offset pins) goes into the stop/tail socket, and the 1156 bulb goes into the turn signal socket. Align the pins with the socket slots, press in, and rotate clockwise approximately 1/4 turn until the bulb locks into the bayonet mount. Tug gently on each bulb to verify it is secured.
9. 9

   Test all light functions
   Before reinstalling the lens, have an assistant turn on the parking lights, press the brake pedal, and activate the turn signal for the side being serviced. Verify that all bulbs illuminate correctly: tail light glows dimly with parking lights, brake light glows brightly when brake is applied, and turn signal flashes. If any function does not work, check bulb installation and socket contacts.
10. 10

    Reinstall tail light lens
    Position the lens over the housing, aligning the screw holes. Ensure the gasket or seal on the lens (if equipped) is properly seated. Install the 4 Phillips head screws and tighten in a cross pattern (top-left, bottom-right, top-right, bottom-left) to distribute pressure evenly. Tighten snugly but do not overtighten, as excessive force can crack the lens.

Reassembly

1. Perform a final test of all tail light functions after lens installation
2. Close the tailgate and inspect the tail light assembly from the rear to ensure proper alignment and seal
3. Repeat the procedure for the opposite side if necessary

Verification

• With the vehicle running, verify parking lights, brake lights, and turn signals all function correctly on the serviced side
• Inspect the lens-to-housing seal for gaps that could allow moisture intrusion
• Check that the lens is secure and does not rattle when the tailgate is closed firmly
• During the next few drives, monitor for condensation inside the lens, which would indicate a faulty seal

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