Technical Service Bulletin #766

Regarding adjustment of Upper Back Panel Limit Switch on 64-66 Thunderbird equiped with the replacement switch with part number C5VY-15A647-C.

Malfunctions with the convertible top and deck lid systems, resulting in premature pump-motor failures, have been experienced in 1966 Thunderbirds. This problem can occur as a result of improper adjustment of the upper back panel limit switch. If not properly adjusted, the limit switch can energize both motor windings simultaneously and interrupt the deck lid opening/closing sequence.

Complaints of improper or incomplete cycling of the convertible top and /or deck lid may be corrected by properly adjusting the upper back panel limit switch. The following procedure should be used in conjunction with Illustration S1033A.

  1. With the deck lid and upper back panel fully extended, disconnect all wiring connectors, Item "A", from the upper back panel limit switch, Item "C".
  2. Loosen the locking screw, Item "D", on the OUTER ring, Item "E", of the upper back panel limit switch, Item "C".
  3. Place a self-powered test light across the black-yellow wiring terminals, Item "B", on the upper back panel limit switch, Item "C".
  4. Rotate the OUTER ring, Item "E", of the switch until the test light goes out. While holding the OUTER ring in this position, tighten the locking screw, Item "D".
  5. Reconnect the wiring connectors to the upper back panel limit switch and actuate the top control switch to retract the upper back panel to the fully closed position. the upper back panel should compress the rubber bumpers on the underside of the deck lid by 30 to 60 percent of normal in the closed position.
  6. Again disconnect the limit switch wire connectors, Item "A", and loosen the locking screw on the INNER adjustment ring, Item "F".
  7. Place a self-powered test light across the red-green with white stripe terminals, Item "G", and rotate the INNER ring, Item "F", until the test light goes out. While the ring is in this position tighten the INNER ring locking screw.
  8. Reconnect the wire connectors and operate the top through two complete cycles to assure proper operation of all top and deck lid components.

Note: In the event that the upper back panel is readjusted to achieve proper flushness and fit with the quarter panels and deck lid, the above switch adjustment procedure must be accomplished prior to complete cycling of the top.

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