Hello All:

This question pertains to my 1994 940 wagon, non-turbo.

My AC vents are cutting out on acceleration or going up a hill, due to loss of vacuum. As soon as I take my foot off the gas, the vents begin blowing again.

However, my defroster and heater are completely unaffected. The recirc works fine too. No change in air volume, even if I floor it up a long hill, except for the dash vents.

I tested the black & white vacuum check valve on the firewall. It is OK.

Is there a separate check valve or solenoid which controls only the dash vents?

If the bellows for the dash vents is leaking & needs replacement, how big a job is that?

Any advice would be appreciated.

Thanks.

JB