a/c, heater vents 91 volvo 940 SE

gyrene · Post by **gyrene** » 07 May 2008, 07:44

A/C and heater vents will not open. When control is placed in the various positions, nothing happens. Sometimes when first started the dash vents are open then they close and it seems the defrost opens somewhat. This is very frustrating please some help.

Thank You

Post by **sseir39** » 07 May 2008, 10:01

Look at the FAQ for RWD on brickboard.com

Being the owner of a 91 940 SE I have experienced such problems. It tends to all be related to vacuum problems. Check your vacuum valves at the intake manifuld. There are two sources there and a leak can mess up all the happenings. Also, there is a valve under the driver side that has two taps. One side of this valve can start to leak so that under accelleration you will lose air flow untill you get off the gas. Patience and studying the flow of vacuum should help you.

gyrene · Post by **gyrene** » 07 May 2008, 11:27

Thanks sseir39 for the info

Kmaniac in California USA · Post by **Kmaniac in California USA** » 16 May 2008, 14:37

Also, check your vacuum reserve tanks for cracks & leaks, as well as all the hoses. I posted about this problem and my solution previously.

gyrene · Post by **gyrene** » 16 May 2008, 19:01

Thax KManiac I'm just going to replace all vacuum lines while in there.