Body, generic

B0290 Rear Defrost Switch Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0290 has no public source: the publicly available J2012 tables omit it, and service literature is silent. The title names the push button that requests the heated rear window. On the 2011 Saab 9-5 (GM) that button sits in the climate control faceplate, which passes the request to the climate module; only the relay output has its own code there (B0283). Saab's 9-3 monitors the button lamp separately as B0969 02. Patents US4555743A and US4673797A describe the usual logic: a momentary switch starts a timer of about ten minutes and can cancel it again. A switch fault means requests are lost or seen all the time, so the rear window either never heats or restarts by itself.

Likely causes

Rear defrost button contacts worn or button stuck in the panel
Climate control faceplate or its circuit board defective
Signal or data line between panel and module interrupted

Symptoms

  • Pressing the rear defrost button has no effect
  • Rear window heating switches on by itself or cannot be cancelled
  • Indicator lamp in the button stays dark or lit

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–300
Time0.3–1.5 h

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

Parts involved

rear defrost switchbody control module

Related codes

B0283B0950

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