B10A1Fresh-air blower diagnosis line: open or short to battery

• Volkswagen group code · Climate control

How the car detects it

The blower motor's control unit reports back to the climate control over a separate diagnosis wire; that wire is open or shorted to battery voltage.

What you may notice

• Blower slow, erratic or not working

Likely causes

• PossibleLoose connector or terminal at the blower control unit
• PossibleFuse or power supply to the blower
• RareBlower control unit

Sources

• static.nhtsa.gov › MC-10149907-9999.pdf · official document
• static.nhtsa.gov › MC-10172984-0001.pdf · official document

Backed by an official manufacturer document.

From Obdaryn's Volkswagen group pack, exactly as the app shows it, with the public sources above. Guidance only; confirm with a workshop.