B0283Rear Defogger Relay Control Circuit
- Generic OBD-II code · Body
- How the car detects it
- B0283 is not in any publicly available J2012 list; it is documented by Saab/GM, where it means the heated rear window relay, not a blower. In the Saab 9-3 (2003–2012) the rear electrical centre sets B0283 01 when the relay output exceeds 6 V with heating on, and B0283 06 when it stays below 6 V (open or grounded line). The GM-built Saab 9-5 and 9-4X of 2011 run the test in the climate module at 9–16 V: 02 means a grounded relay control line and the grid heats nonstop, 05 means open or short to voltage and the grid stays cold; a history code clears after 50 ignition cycles. As US4673797A shows, such relays are usually timed and drop out after a set period. Front blower faults belong to B0181/B0186; the heating grid itself is B0950.
- What you may notice
- Heated rear window does not work when switched on
- Rear window heats continuously and cannot be switched off
- Battery drained if the grid keeps heating
- Likely causes
- LikelyRear window heater relay with open coil or welded contacts
- PossibleRelay control wire open, grounded or shorted to battery voltage
- PossiblePoor ground or corroded socket at the relay
- RareOutput stage of the climate or electrical centre module faulty
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.