This procedure covers the removal and replacement of the heater control valve on a 2012-2018 Jeep Wrangler JK with the 3.6L V6 engine, which regulates coolant flow to the heater core.

Warnings

Tools required

Parts

• Heater control valve × 1 — Mopar 68079487AA or equivalent
• Hose clamps (if reusing existing clamps are damaged) × 2 — Use OEM specification
• Mopar OAT Coolant (Purple) × 1 — Mopar 68051212AC

Fluids

• Mopar OAT Coolant (Purple) — 2 qt

Preparation

1. Ensure engine is completely cold to the touch (wait at least 2 hours after last operation)
2. Park vehicle on level ground and engage parking brake
3. Place drain pan under vehicle beneath radiator drain petcock location
4. Disconnect negative battery terminal and secure cable away from battery
5. Locate heater control valve on passenger side firewall area near heater hoses

Procedure

1. 1

   Drain coolant from system
   Remove radiator cap slowly to release any residual pressure. Locate the drain petcock on the bottom driver side of the radiator. Open the petcock and drain approximately 2 gallons of coolant into the drain pan. Once drained, hand tighten the petcock.
   Torque spec

   Drain Petcock8 Nm (6 lb-ft)
2. 2

   Locate and access heater control valve
   The heater control valve is mounted on the passenger side firewall, in-line with the heater hoses. Trace the heater hoses from the engine to the firewall to identify the valve assembly. It will have an electrical connector attached.
3. 3

   Disconnect electrical connector
   Locate the electrical connector on the heater control valve. Press the release tab and pull the connector straight off the valve. Do not pull on the wiring harness itself.
4. 4

   Remove inlet hose clamp and hose
   Using a flathead screwdriver or hose clamp pliers, loosen the hose clamp on the inlet side (engine side) of the heater control valve. Slide the clamp back on the hose away from the valve. Twist and pull the hose off the valve inlet. Additional coolant will drain; have shop towels ready.
5. 5

   Remove outlet hose clamp and hose
   Loosen the hose clamp on the outlet side (heater core side) of the valve. Slide the clamp back on the hose. Twist and pull the hose off the valve outlet. More coolant will drain from this connection.
6. 6

   Remove heater control valve mounting
   The heater control valve is typically mounted with a bracket or clip to the firewall. Remove any retaining clips or fasteners securing the valve to its mounting bracket. Carefully pull the valve free from the mounting location.
7. 7

   Install new heater control valve
   Position the new heater control valve in the mounting location on the firewall. Secure with the mounting bracket or clips, ensuring the valve is properly oriented with inlet toward engine and outlet toward heater core. The electrical connector should be easily accessible.
8. 8

   Connect coolant hoses
   Install the inlet hose onto the engine-side connection of the new valve, pushing firmly until fully seated. Slide the hose clamp into position over the connection and tighten. Repeat for the outlet hose on the heater core side. Ensure hoses are fully seated before tightening clamps.
   ⚠Do not overtighten hose clamps as this can damage the valve connections or hoses. Use torque wrench to verify proper tightness.
   Torque spec

   Hose Clamps4 Nm (3 lb-ft)
9. 9

   Reconnect electrical connector
   Push the electrical connector onto the new heater control valve until it clicks into place. Verify the connection is secure by gently tugging on the connector body (not the wires).
10. 10

    Refill cooling system
    Using a coolant funnel in the radiator fill neck, slowly add Mopar OAT purple coolant to the system. Fill the radiator to the top of the fill neck. Also fill the coolant recovery reservoir to the MAX cold fill line. Allow coolant to settle and top off as needed.
11. 11

    Bleed air from cooling system
    Reconnect the negative battery terminal. Start the engine and allow it to warm up to operating temperature with the radiator cap off. Run the heater on high temperature and high fan speed. As the thermostat opens and coolant circulates, air will be purged from the system. Add coolant as the level drops. Once the engine reaches operating temperature and the upper radiator hose is hot, the system is bled.
    ⚠Monitor coolant level closely during bleeding process. Never allow the system to run dry as this will introduce more air and can cause overheating.
12. 12

    Final coolant top-off and cap installation
    With engine at operating temperature, top off the radiator to the fill neck. Install the radiator cap securely. Check the recovery reservoir and ensure level is at the HOT fill line. Allow engine to cool, then verify reservoir is at COLD fill line when cool.

Reassembly

1. Double-check all hose clamps are properly tightened to specification
2. Verify electrical connector is fully seated and locked onto heater control valve
3. Inspect all coolant connections for leaks while engine is running and after cool-down
4. Ensure no tools or parts were left in engine compartment

Verification

• Start the engine and verify no coolant leaks at heater control valve connections
• Turn heater controls to maximum heat and verify hot air is produced inside cabin
• Monitor engine temperature gauge to ensure normal operating temperature is maintained
• Check coolant level after 24 hours of driving and top off if necessary
• Verify heater control valve operation by switching between heat and vent modes; temperature should change accordingly

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