B0290Rear Defrost Switch Circuit
- Generic OBD-II code · Body
- How the car detects it
- 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.
- What you may notice
- 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
- Likely causes
- LikelyRear defrost button contacts worn or button stuck in the panel
- PossibleClimate control faceplate or its circuit board defective
- RareSignal or data line between panel and module interrupted
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.