e39 a/c warm on one side

[8 POTS]

My 2001 e39 525I has auto a/c climate control system. The right hand side of the ac does not cool down as fast as left and does not either go as low when cooled.

-I have thorougly checked all servo actuators and flap operation.
-Also checked heater valves, not open on one side, all pipes remain cool. (ac not fighting heater)
-Also checked temperature sender units (left and right) inside airbox. both read same resistance at rest and increase with ac on, but right then stops. (temp does not drop further)
-Swapped sender units around and still no change in problem.
-air volume coming out both sides the same.

Can the AC be low on charge? Surley if yes both sides should be less efficient but equal?

This feels really strange to me, as far as I know e39 auto system uses dual sided heater cores to control temp, but there is only one evaporator core through which both sides pass.

Anybody got an idea what could be the problem?

[8 POTS]

Ok guys I know it is a e39 query in e34 territory, but if i could find e34 with in similair condition and mileage I would take it. If you have a suggestions with regard to ac problem in previous post please let know.