Do they use a split heater core system? I though it was one heater core one evap core 2 blend doors and 2 mode doors. A heater control valve wouldn't account for one side if my thought process is correct (i am exhausted so it very well could be wrong)

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12 x5 35d (e70)

03 530i (e39)
02 540i (e39)
97 z3 (e36)
05 630ci (e63) [totaled]