Electric rear defrost circuit low
What it means
B0285. Electric rear defrost circuit low. The defrost grid current reads low and the rear glass may not clear. This Chevy-enhanced code applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.
Findings, check these first
- Broken grid tab or open element in the rear glass
- High resistance in the rear defrost power circuit
- Blown or corroded rear defrost fuse
- Failed rear defrost relay with a weak contact
- Faulty output inside the body control module
Standard procedure
- Confirm the code with a scan tool and command the rear defrost on
- Measure the rear defrost grid current and compare to spec
- Test each rear defrost grid line for continuity
- Check the rear defrost fuse, relay and power wiring
- Repair the broken grid line or tab only after the circuit tests pass, then clear the code and retest
Look up another code
Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.
Sources and review
Review: checked against the recorded source material.
- Code B0285 definition | OBDII.pro
live manufacturer definition (obdii.pro)
Supports: GM manufacturer meaning for B0285
Fetched directly. The GM entry is the brand-family meaning used here. This site is independent of engine-codes and autocodes.
- B0285 CHEVROLET Electric Rear Defrost Circuit Low | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: Chevrolet meaning and possible causes for B0285
Fetched directly. Model and year fitment remain curator claims.
- B0285 CHEVROLET Electric Rear Defrost Circuit Low | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Chevrolet meaning and causes for B0285
Same Chevrolet text as the engine-codes page (both sites share one publisher).
Last updated 2026-10-10.
Report a correction for B0285. Include your vehicle, the issue and a source if you have one.