Body, generic

B0820 Left Headlamp High Beam Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0820 is undocumented: neither open J2012 material nor factory or NHTSA papers list it. The title refers to the left main-beam output. In the second-generation Saab 9-3 the front electrical centre flags B2580 04 when the left main beam draws under 0.8 A while switched on and B2580 0B for 7.9 to 30 A. GM's 2011 Saab 9-5 works differently: both main beams are fed through one relay whose coil the body control module grounds, and if that control line is shorted to battery plus, B2580 01 is stored with both high beams off. HELLA points out that bi-xenon units form low and high beam in one module by moving a shutter, so a fault can also sit in that mechanism. FMVSS 108 requires an upper-beam indicator for the driver. Right side: B0821.

Likely causes

Left high-beam bulb burnt out
High-beam relay or its control line faulty
Shutter actuator in a bi-xenon module stuck
Corroded headlamp connector

Symptoms

  • Left main beam stays dark when high beam is selected
  • Both main beams fail if the shared relay circuit is affected
  • Lamp failure message in the display

Repair estimate

DifficultyEasyDIY possible
Parts and labour€10–500
Time0.2–2 h

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

Parts involved

left high beam lampbody control module

Related codes

B0821B0810B0800

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, hella.com.