OBD-II code · Body
B0290 Rear Defrost Switch Circuit
The body control module has detected a fault in the rear window defroster switch circuit. The switch may be stuck or its signal does not reach the module — the rear defroster cannot be activated.
Is it safe to drive with B0290?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyDefrost switch failed
- PossibleWiring or connector fault
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Rear Defrost Switch, Body Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.