Climate control unit part numbers


Fire up the Quattro!
VCDS Map User
The climate control unit is temperamental in my friends 2000 X Allroad. Passenger side heat settings sometimes just randomly goes down by 0.5 degrees at a time.

The part number is 4B0 820 043K. I have a unit from an 2002 Allroad part number 4B0 820 043AK and this doesn't work. Econ light stays on and has 4 faults every time I clear them. Yet the original HVAC unit works perfectly except passenger heat. Air con works as it should.

The coding options for the two are different.

Does anyone know what other part numbers are compatible with the 'K' denoted part number?