A/C EATC Control Assembly Dial Bulb Replacement (85-4-4)

A/C EATC CONTROL ASSEMBLY DIAL BULB REPLACEMENT

TECHNICAL SERVICE BULLETIN

AIR CONDITIONING - EATC CONTROL ASSEMBLY DIAL ILLUMINATION BULB REPLACEMENT

APPLICATION

Model(s): FORD: 1985 THUNDERBIRD

LINCOLN-MERCURY: 1984-85 CONTINENTAL, MARK VII, COUGAR

Group: Air Conditioning

Bulletin No.: 85-4-4

Date: February 21, 1985

SERVICE INFORMATION

The following service procedure is to be used only on vehicles beyond the warranty period and is only for replacement of the dial illumination light bulbs. This procedure does not apply to the vacuum fluorescent (VF) display or the function indicator lights (LEDs). If the numerical VF display or any of the function LEDs are inoperative or if the system is still covered by the new vehicle warranty, the entire control assembly must be replaced.

SERVICE PROCEDURE

1. Remove the control assembly from the vehicle.
2. Place the control assembly on a clean cardboard surface and cut the white tape seal over the joint of the button housing and the control housing (see Fig 1 ).
3. Remove the two (2) screws (A, Figure 1) from the bottom of the control housing.
4. Remove the two (2) screws (B, Figure 1) attaching the control housing to the button housing.
5. Rotate the top of the button housing slightly downward to disengage the hooked tabs on the bottom of the button housing from the control housing. Then, gently slide the button housing and circuit board assembly approximately 3 inches out of the control housing. To protect the circuit board, do not completely remove it from the control housing. See Fig 1 .
   CAUTION: DO NOT TOUCH the components or traces on the circuit board as damage to the circuit and/or components can result.
   NOTE: Care should be used not to excessively flex the ribbon cable between the button housing assembly and the circuit board.
6. The gray rectangular plastic bulb and socket assemblies protrude from the back of the button housing circuit board - one on each side. See Fig 1 . To remove the bulb and socket assembly, carefully start rotation counterclockwise with pliers, taking care not to touch any other components with the pliers. Continue rotation by hand (approximately 45°) to the stop and pull the bulb and socket assembly straight out from the button housing.
7. Pull the old bulb from the socket and install a new bulb, Part Number D4AZ-13466-A (Trade No. 37), in the socket.
8. Re-install the bulb and socket assembly into the button housing and rotate clockwise (approximately 45°) to lock the socket assembly in place. DO NOT USE PLIERS TO INSTALL THE SOCKET ASSEMBLY.
9. Check to be sure the main circuit board is between the grooves molded inside the control housing. Then, slide the circuit board assembly completely into the control housing and engage the tabs on the button housing with the control housing.
10. Install screws A and B, re-install the control assembly in the vehicle, and perform the EATC functional test