Safe to drive; climate-comfort fault only. B10A2 means the A/C-Heater control detected a performance problem on the LEFT blend-door actuator's control (driver) circuit — typically a short — so the control can't reliably position the left temperature door and that side of the cabin misbehaves.
What B10A2 means
On a dual-zone (ATC) 300C, Charger or Magnum, the A/C-Heater control drives each blend-air door through a two-wire door-driver circuit and monitors it. B10A2 is a 'control circuit / performance' code: it sets when that circuit on the LEFT actuator behaves abnormally — most often shorted to voltage, to ground, or wire-to-wire — so the door can't be driven properly. The left side of the cabin then sticks or swings erratically. 'Left' is the physical left of the vehicle (the driver's side on a left-hand-drive car).
Symptoms
- The left side of the cabin is stuck or erratic and ignores the temperature setting
- Possible clicking or no movement from the left blend-door actuator
- The right side of the dual-zone system still works normally
- B10A2 stored in the A/C-Heater module
Common causes
- Left blend-door driver circuit shorted to voltage, to ground, or wire-to-wire
- Chafed or pinched harness or a corroded connector at the actuator
- Internally shorted left blend-door actuator
- Faulty A/C-Heater control (module)
Severity & driving advice
Severity: Low — Comfort fault only — safe to drive; a scan tool and the wiring diagram are needed to diagnose.
Can I drive? Safe to drive; climate-comfort fault only.
Diagnostic approach
- Read the HVAC codes — Confirm B10A2 and repair any left-door Control Circuit Open code first.
- Inspect the actuator circuit for shorts — Check the two left door-driver wires and the connector for chafing, pinching, or corrosion and for a short to voltage, ground, or each other. Repair before testing the actuator.
- Substitute the actuator — If the wiring is clean, replace the left blend-door actuator and run the calibration.
- Replace the control if the code returns — If a good circuit and a new actuator still set B10A2, suspect the A/C-Heater control module.
Estimated repair costs
Typical US repair costs (parts & labour) for the faults behind B10A2. These are national-average estimates, not a quote— your actual price varies by region, shop labour rate, and your vehicle’s make, model and year. Figures reviewed 2026.
| Repair | Estimated cost (USD) |
|---|---|
| Wiring / connector repair | $80–$260 |
| Blend-door actuator (part) | $15–$90 |
| Actuator replacement + calibration (shop) | $90–$250 |
Make & model notes
Chrysler / Dodge / Jeep: B10A2 is the dual-zone (ATC) LEFT blend-door 'control circuit / performance' code on LX-platform cars (300 / 300C, Charger, Magnum) and related FCA models — the mirror of B10A9. It usually means a short on the left actuator's driver circuit; inspect the harness and connector before replacing the actuator (Section 8W wiring), and calibrate after any actuator or control-head change. (Note: some non-FCA makes use B10A2 for an unrelated fault — this page covers the FCA dual-zone blend-door meaning.)
FAQ
Is B10A2 the same as B10A9?
On these FCA cars they are mirror codes: B10A2 is the LEFT blend-door 'control circuit / performance', B10A9 is the RIGHT. Same electrical fault type, opposite sides.
What usually causes B10A2?
A short on one of the left actuator driver wires — often a chafed harness or a corroded connector — or an internally shorted actuator. Inspect the wiring and connector first.
Is B10A2 safe to drive with?
Yes — it only affects climate comfort on the left side of the cabin.