Safe to drive; climate-comfort fault only. B10A5 means the LEFT blend-door actuator's control (driver) circuit is open — a break in the wiring, connector, or actuator — so the A/C-Heater control can't move the left temperature door and that side of the cabin is stuck.
What B10A5 means
On a dual-zone (ATC) 300C, Charger or Magnum, the A/C-Heater control drives each blend-air door over a two-wire door-driver circuit. B10A5 sets when that circuit reads OPEN on the LEFT actuator — the path is broken, the actuator gets no drive, and the left temperature door can't move. That side of the cabin stays at whatever temperature the door was last left at. '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 at one fixed temperature
- No movement or sound from the left blend-door actuator
- That side does not respond to the temperature setting
- B10A5 stored in the A/C-Heater module
Common causes
- Open (broken) wire in either of the two left blend-door driver circuits
- Disconnected or corroded connector at the actuator or control module
- Left blend-door actuator with an open internal winding
- 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 for the circuit test.
Can I drive? Safe to drive; climate-comfort fault only.
Diagnostic approach
- Read the HVAC codes — Confirm B10A5 on the A/C-Heater module and note companion codes.
- Inspect the actuator connector — Unplug the left blend-door actuator and check for backed-out, corroded, or spread terminals; reseat and retest.
- Test the two driver wires for an open — Using the wiring diagram, check continuity of both left door-driver circuits between the control connector and the actuator. Repair any open.
- Replace the actuator, then the control if needed — If wiring and connectors are good, replace the left blend-door actuator and calibrate. If B10A5 persists, suspect the A/C-Heater control module.
Estimated repair costs
Typical US repair costs (parts & labour) for the faults behind B10A5. 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: B10A5 is the dual-zone (ATC) LEFT blend-door 'control circuit open' code on LX-platform cars (300 / 300C, Charger, Magnum) and related FCA models — the mirror of B10AC. It points at the wiring path first: check the actuator connector and the two door-driver wires (Section 8W wiring diagram) before replacing the actuator. Calibrate after any actuator or control-head change.
FAQ
Is B10A5 the same as B10AC?
They are mirror codes: B10A5 is the LEFT blend-door 'control circuit open', B10AC is the RIGHT. Same electrical fault, opposite sides.
What usually causes B10A5?
An open in one of the two actuator driver wires, or a disconnected/corroded connector — check the connector at the actuator first, then the wiring, then the actuator itself.
Can I drive with B10A5?
Yes — it only affects climate comfort on the left side of the cabin.