Rear Ac works front Not

[Mike]

1989 635, rear "cooler" AC works and is icy cold, no cooling in the front vents- any ideas?

[TimU]

This is a typical sign of a failed "Voltage Regulator" which controls the coolant flow between the front and rear evaporator coils.

The VR is located in the engine bay, part number 64511380659.

https://www.realoem.com/bmw/enUS/showpa ... 4511380659

[emac]

Hope it's not the "voltage regulator" as they dont appear to be available anymore. I think it was made by Denso. I contacted them a year or so ago and they said it was made for BMW and not available for sale.

Currently my AC has the same issue, pretty certain it is low on freon as the VR is only a few years old.