Body, generic

B0263 HVAC Air Mix Door 2 Circuit

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

B0263 shares the fate of its sibling B0258: no publicly available J2012 source lists it and no maker describes it. The second blend door usually serves the passenger side or the rear zone. Saab's 9-5 and 9-4X service data, which follow GM's Global A scheme, file the right temperature actuator under B0418 and the rear one under B0428, each a stepper motor checked for shorts to voltage and for opens. Some designs save the second motor: Denso's US7793706B2 drives the front door and a pair of rear doors from one servo through cams and a rocker, so a single failure would affect both zones. When the second door's circuit fails, the passenger or rear side stays at a fixed temperature while the driver side keeps regulating.

Likely causes

Passenger-side or rear blend actuator failed

Wiring to the second actuator open or shorted, often near the centre console

Shared linkage or door shaft broken, overloading the drive

Symptoms

Passenger side or rear outlets stay at one temperature whatever is set
Noticeable temperature difference between left and right outlets

Repair estimate

DifficultyMediumDIY possible

Parts and labour€80–500

Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hvac air mix actuator 2hvac control module

Related codes

B0258 B0168

References: saabwisonline.com, patents.google.com, patents.google.com.