The blend door actuator is a small motor on the HVAC box that moves the door mixing hot and cold air. When it fails on a JK you get hot hoses at the firewall but cold air at the vents, often with a clicking from behind the dash. Mopar 68018109AA is the main blend actuator, crossed by Dorman 604-029.
Fitment
Parts catalogs list it as the main blend actuator for 2011–2018 JKs. Dorman says its actuators are position-specific, so check fit by year. Always confirm the number on your old part or run your VIN at a Mopar parts counter before you order.
Common failure symptoms
- Both heater hoses hot at the firewall but the vents blow cold or lukewarm
- Clicking or ticking behind the lower dash when you change the temperature
- Temperature doesn't change when you turn the knob
- Works on one setting but not across the full hot-to-cold range
Cross-reference
| Brand | Part number | Notes | Source |
|---|---|---|---|
| Mopar | 68018109AA | OEM main blend door actuator. | source |
| Dorman | 604-029 | Crosses to 68018109AA. Position-specific; check fit. | source |
Rebuild, repair or replace?
Actuators aren't rebuilt; you replace them. But confirm it's the actuator first. Warm the Jeep fully, set full heat, and feel both heater hoses. If one is cold, you have a coolant problem (low coolant, air, or a stuck thermostat), not an actuator problem. If both are hot and the air is cold, the actuator is the likely fault.
On a JK the main actuator is on the left side of the HVAC box, under the steering column. The factory manual calls it a two-screw job (17 in-lbs), but you have to remove the driver's lower dash and floor duct to get to it, so plan on an afternoon. JLs are different: they often respond to an HVAC calibration with a scan tool before any parts get replaced.
Where to buy
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FAQ
How do I know it's the actuator and not the heater core?
Hot inlet and outlet hoses with cold vent air points to the blend door. One cold hose points to coolant flow.
Is it hard to replace?
Two screws, but you have to remove the lower dash on the driver's side first.
Does the JL use this part?
No. JL HVAC issues often start with a scan-tool recalibration.
Related guides
Sources
Part numbers and fitment were checked against the sources above on October 22, 2026. Mopar supersedes numbers over time. If a newer letter suffix shows up, it generally replaces the one listed here. Back to the parts lookup.