Remove and replace the heater control assembly (climate control module) on a 1966 Chevrolet Corvette, including cable and vacuum line disconnection.

Warnings

Tools required

Parts

• Heater control assembly × 1 — Use OEM specification
• Control cable clips × 3 — Use OEM specification

Preparation

1. Disconnect negative battery cable to prevent electrical shorts
2. Allow engine and heater system to cool completely
3. Position driver's seat fully rearward for access
4. Prepare labels or masking tape to mark vacuum line routing

Procedure

1. 1

   Remove radio knobs and bezel
   Pull off the radio control knobs by hand. Remove the 2 screws securing the radio bezel trim panel. Carefully pull the bezel forward to access the heater control assembly behind it.
2. 2

   Label and disconnect vacuum lines
   Using masking tape and marker, label each vacuum line connected to the back of the heater control assembly. Note the color coding (typically red, blue, yellow, and green lines). Carefully pull each vacuum line connector straight off the control assembly nipples. There are 4 vacuum line connections on the 1966 Corvette heater control.
3. 3

   Disconnect temperature control cable
   Locate the temperature control cable attached to the right side of the control assembly. Using needle-nose pliers, squeeze the cable clip retainer and slide it off the cable housing. Pull the cable end fitting straight out from the control lever arm to disconnect.
4. 4

   Disconnect blower switch wiring
   Reach behind the control assembly and locate the wire connector for the blower switch. Press the locking tab and pull the connector straight off. If the connector is tight, use a flat-blade screwdriver to carefully pry it while pulling.
5. 5

   Disconnect heater control light wire
   Locate the small bulb socket on the back of the control assembly (used for dashboard illumination). Rotate the socket counterclockwise 1/4 turn and pull it straight out from the housing.
6. 6

   Remove control assembly mounting screws
   Remove the 4 screws securing the heater control assembly to the instrument panel. Two screws are located at the top of the assembly and two at the bottom. Use a Phillips screwdriver or 1/4-inch socket depending on screw head type.
7. 7

   Remove control assembly
   Carefully pull the heater control assembly straight out from the instrument panel. Maneuver it to clear any remaining wiring or cables. Inspect the mounting area for debris or damage.
8. 8

   Transfer components to new assembly
   If applicable, transfer the blower switch and temperature control knobs from the old assembly to the new unit. Ensure the light bulb socket is functional or install a new bulb if needed.
9. 9

   Install new control assembly
   Position the new heater control assembly into the instrument panel opening. Align the mounting holes with the panel and hand-start all 4 mounting screws before tightening. Tighten screws evenly to secure the assembly without over-tightening and cracking the plastic.
10. 10

    Reconnect heater control light
    Insert the bulb socket into the back of the control assembly and rotate clockwise 1/4 turn to lock it in place.
11. 11

    Reconnect blower switch wiring
    Push the blower switch wire connector onto the terminals at the back of the control assembly until the locking tab clicks into place.
12. 12

    Reconnect temperature control cable
    Attach the temperature control cable end fitting to the control lever arm. Slide the cable clip retainer over the cable housing and press firmly until it locks. Verify the cable moves smoothly through its full range of motion by operating the temperature control lever.
13. 13

    Reconnect vacuum lines
    Using the labels created earlier, reconnect each vacuum line to its corresponding nipple on the back of the control assembly. Push each line firmly onto the nipple until it seats completely. Verify all 4 lines are securely attached.
14. 14

    Reinstall radio bezel
    Position the radio bezel trim panel and secure with the 2 mounting screws. Reinstall the radio control knobs by pressing them onto the shafts.

Reassembly

1. Reconnect negative battery cable
2. Verify all control knobs and levers move freely through their full range
3. Return driver's seat to normal position

Verification

• Turn ignition to accessory position and verify heater control illumination works
• Start engine and test blower motor operation at all speed settings
• Verify temperature control operates correctly by moving lever from full cold to full hot
• Test all mode positions (defrost, vent, heat) and listen for vacuum actuator operation
• Check for proper airflow from selected vents in each mode
• Verify no vacuum leaks are present by listening for hissing sounds behind the dashboard

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