This procedure covers the replacement of a seat heater element in a 1966 Chevrolet Corvette, requiring removal of the seat from the vehicle and disassembly of the seat upholstery to access the heating element.

Warnings

Tools required

Parts

• Seat heater element × 1 — Use OEM specification or aftermarket equivalent
• Hog rings × 1 — 3/8" upholstery hog rings
• Wire connectors or crimp terminals × 1 — Use as needed for electrical connections
• Electrical tape × 1 — Standard automotive electrical tape

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable to isolate electrical system
3. Move seat to full forward position to access rear mounting bolts
4. Label or photograph all electrical connectors before disconnection
5. Prepare clean work area with blankets or protective covering to place removed seat

Procedure

1. 1

   Test and verify heater element failure
   Before removal, use a multimeter to test the seat heater element resistance. Access the heater element connector under the seat. Note that since this is not a factory system, the connector type and location depend entirely on how the aftermarket heater was installed. With the multimeter set to ohms, test across the two pins. A functioning element should show resistance between 2-5 ohms. An open circuit (infinite resistance) or very low resistance (short) indicates element failure. Document the reading to confirm replacement is necessary.
2. 2

   Disconnect seat electrical connections
   Locate all electrical connectors under the seat. If an aftermarket seat heater has been installed, locate its power connector under the seat. Carefully disconnect the heater element connector by pressing the release tab and pulling straight apart. Use masking tape and marker to label the connector for reassembly.
3. 3

   Remove seat track mounting bolts
   With the seat in the full forward position, locate and remove the rear seat track mounting bolts. Slide the seat to the full rear position and remove the front seat track mounting bolts. Confirm the exact bolt count, head size, and mounting method (bolts into captive nuts vs. studs with nuts) against a 1966 Corvette assembly manual before proceeding.
4. 4

   Remove seat assembly from vehicle
   With all mounting bolts removed and electrical connections disconnected, carefully lift the seat assembly straight up and out of the vehicle. The seat may be heavy, so use proper lifting technique. Place the seat upside down on a protected work surface with the bottom facing up.
5. 5

   Remove seat bottom trim panel
   Inspect the underside of the seat bottom for the trim panel or dust cover. Remove any screws or clips securing this panel using a flat blade screwdriver or trim removal tool. This panel protects the seat springs and upholstery attachment points. Set aside all fasteners for reinstallation.
6. 6

   Access seat upholstery hog rings
   With the seat inverted, locate the hog rings that secure the seat cover to the seat frame. These metal rings are typically spaced 3-4 inches apart around the perimeter of the seat bottom. The heater element wiring will be visible running between the foam padding and the seat frame.
7. 7

   Remove hog rings from seat perimeter
   Using hog ring pliers or needle nose pliers, carefully remove the hog rings securing the seat upholstery to the frame. Start at the rear of the seat and work forward, removing approximately 15-20 hog rings around the perimeter. Store the removed hog rings if they are in good condition for potential reuse, though new rings are recommended.
8. 8

   Carefully separate upholstery from foam
   With hog rings removed, gently pull the seat cover away from the foam padding. Work slowly and carefully to expose the seat heater element, which is typically sandwiched between the foam pad and the upholstery material. Note the orientation and routing of the heater element wiring. The element may be attached to the foam with adhesive or sewn into a fabric sleeve.
9. 9

   Disconnect and remove failed heater element
   Trace the heater element wiring to its connection point. If the element is spliced into the wiring harness, cut the wires 3-4 inches from the element, leaving enough wire for reconnection. If connected via terminals, disconnect at the terminals. Carefully peel or cut away any adhesive holding the element to the foam padding. Remove the old element completely and inspect the foam for any damage from the failed element.
10. 10

    Install new seat heater element
    Position the new heater element on the seat foam in the same location and orientation as the original. Ensure the element lies completely flat with no wrinkles, folds, or creases, as these can cause hot spots and premature failure. If the element has adhesive backing, peel the protective film and press firmly onto the foam. If no adhesive is present, the element will be held in place by the upholstery tension. Route the element wiring toward the rear of the seat where it will exit to the connector.
11. 11

    Connect heater element wiring
    Connect the new heater element wiring to the existing harness. If the previous connection was cut, strip 1/4 inch of insulation from each wire. Match wire colors (typically red to red, black to black, or positive to positive, negative to negative). Use crimp connectors or solder connections, ensuring secure electrical contact. Cover all connections with electrical tape or heat shrink tubing. Verify polarity if the element is directional.
12. 12

    Test new heater element before reassembly
    Before reinstalling the upholstery, reconnect the battery negative cable temporarily. Connect the heater element connector and activate the heater using whatever switch or control the aftermarket installation provides. Allow the element to warm for 2-3 minutes, then carefully feel the surface of the element through the foam to confirm even heating across the entire surface. Check for any cold spots or excessive heat. Use the multimeter to verify proper resistance. Once confirmed operational, disconnect the battery again before continuing.
13. 13

    Reinstall seat upholstery
    Position the seat cover back over the foam padding, ensuring the heater element remains flat and properly positioned. Pull the upholstery edges down and around the seat frame to the attachment points. Starting at the center rear of the seat, use hog ring pliers to install new hog rings through the upholstery material and around the seat frame wire. Work from center to sides, maintaining even tension on the upholstery. Install hog rings approximately 3-4 inches apart around the entire perimeter, ensuring the cover is smooth and tight without wrinkles.
14. 14

    Reinstall seat bottom trim panel
    Position the seat bottom dust cover or trim panel back in place on the underside of the seat. Ensure the heater element wiring is properly routed through any designated openings and not pinched. Reinstall all screws or clips to secure the panel, ensuring it is seated flush against the seat frame.
15. 15

    Reinstall seat assembly in vehicle
    Carefully lift the seat assembly and position it over the mounting locations in the vehicle. Align the seat track mounting holes with the floor pan captive nuts. Install the seat track mounting bolts finger-tight initially, then tighten them securely in a cross pattern to the manufacturer-specified torque. Confirm the bolt count and head size against a 1966 Corvette assembly manual. Reconnect the heater element electrical connector, ensuring the connection is fully seated and locked. Verify the wiring is not pinched or stressed.

Reassembly

1. Reconnect the negative battery cable
2. Test seat heater operation at all heat settings before final verification
3. Verify seat slides freely on tracks after reinstallation
4. Inspect upholstery for proper tension and alignment

Verification

• Turn ignition to accessory position and activate seat heater switch
• Allow heater to warm for 5 minutes and verify even heat distribution across seat surface
• Check that heater element does not create excessive heat or hot spots
• Use multimeter to verify proper current draw (typically 3-5 amps for seat heater)
• Confirm no electrical smell or burning odor from seat
• Verify seat mounting bolts are secure and seat does not rock or move on tracks
• Test seat adjustment mechanism operates normally without binding

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