Body, generic

B0283 Rear Defogger Relay Control Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Rear window heater relay with open coil or welded contacts
Relay control wire open, grounded or shorted to battery voltage
Poor ground or corroded socket at the relay
Output stage of the climate or electrical centre module faulty

Symptoms

  • 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

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–250
Time0.3–1.5 h

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

Parts involved

rear defrost relayrear window heating elementhvac control module

Related codes

B0290B0950

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