B0305HVAC Sun Load Sensor Circuit
- Generic OBD-II code · Body
- How the car detects it
- B0305 is unconfirmed by any public J2012 list or manufacturer, and its subject matches B0156. The sun load sensor is a photodiode on top of the dashboard that tells automatic climate control how much solar heat enters the cabin (US6888120B2, US5957375A). Real codes for it carry other numbers: Saab's 9-3 uses B0183 08 for an implausible signal and B0184 06 for an open or grounded circuit, and then regulates as if the sky were overcast; the GM-built 2011 Saab 9-5 reports B0183 02/05. A circuit fault rarely stops the system, but in strong sun the cabin tends to run warm and the blower reacts late.
- What you may notice
- Cabin too warm in bright sunshine with auto climate
- Blower speed does not rise when the sun comes out
- Likely causes
- LikelySun load sensor photodiode aged or damaged
- PossibleSensor unclipped from the dashboard grille, connector pulled off
- RareSignal or ground wire to the sensor open or shorted
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.