The car is a 97 960 130K mi

I cannot get the air conditioning controller unit to switch between the different vent modes (floor, auto, etc..). The A/C seems to be working great, however the vent seems to be stuck somewhere between defrost and floor so the air just seeps out even when in full blast.

When I first got the car, the vent selector (or whatever it is) would occasionally get stuck but eventually fix itself. Unfortunately, it's stuck again and unresponsive to the center **** on the climate control system. (Every other button is working fine)

I've removed the climate control unit and carefully taken it apart. It appears to be in really good shape, no broken solder joints or burned spots on the board. The vent selector switch seems to be in good shape as well.

Anyone have any insight of where I should look next?

 

the vacuum diaphragm(s) are bad. the one that swtiches to the vents is a real pain. the dash has to come out.

 

Sorry to say, I've had the same problem for over a year.

I had read that the diaphragm is controlled by vacuum tubes. Thus the position of the air through the vents was dependent upon strong vacuum. The directional change will fail if one of the one-way valves on the vacuum hoses fail, or if there is insufficient vacuum in the vacuum reservoir (i.e. crack in the reservoir).

First I would check the one-way valves, or add another reservoir, or find the leak.

I am happy to say that on my drive back from Eastern Washington today I went over a rather large bump, then the directional control began to work again. I can only assume that the diaphragm was stuck, as the previous poster mentioned, and that it broke free. I'm not going to second guess the end result- directional control that works perfectly well.

TBD

 

I have the same issue. Can you point me to the location of the vacuum reservoir, and is there a good vacuum diagram somewhere. The one-way valves are white/black plastic units right? Which way should they be installed? I just had some engine work done before the problem showed up, and I'm hoping it could be as simple as something put back on backwards.

 

I have the exact same problem, down to every little detail, even LOOKING for bumps to get the damn thing working again, so it sound like the diaphragm from what you are all saying.

Was there a diagram to find this part? I've got no clue on this one....

Funny thing was I test drove another 960 and it did the exact same thing mine did, it would work on start up, then upon driving away/out of the driveway or getting under way, it would cut out on acceleration and cut back in when the powerband smoothed out and I was cruising at low rpms.

But I'd would really like to fix this, I recently had my cowl off to get at the wiper transmission, and moved the door for the vent cut off manually, and it somehow made it work again, but it went back after I switched it to floor to see if it "Magically" was working again. No such luck.

 

My "bump in the road" fix only worked for a week. I checked the one way valves (passenger side, just below the hood, all the way to the back of the engine compartment, i.e. closest to the rear of the wagon) and they work. After 20 years, though, all the rubber hoses in my 960 are getting looser and losing seal.

I will likely wait until spring, when it is raining outside less, and take some time to replace all the vacuum hoses.

Does anyone recommend a vacuum hose kit for these wagons?

Best- TBD

 

Anyone ever locate a FSM diagram for the diaphragm? Might be tearing into this soon.

 

Mine is the same way. First I replaced the vacuum connectors on the passenger side where the A/C goes into the firewall. That worked for a short while & then back to no working again. Today I went to the auto parts & replaced every vacuum line that I could find. Still no good. Not sure I want to try & remove the dash. I'm going to call an small independent garage that specializes in older Volvo's and see how much to fix it right. I'll let you know the results.

 

Fixed the A/C vent problem. My neighbor came over & started looking under my dash to find the vacuum lines that might be a problem. Turns out the air flap actuator solenoid valve had a hairline crack in one of the solder joints. He took a small solder gun and heated it up to seal the crack. It works perfect now. All vents switch properly. The unit is located under the right side of the dash. Remove the bottom panel which just is held on with one screw. The unit is easy to get to. I did check & a new part runs $175-185 at a few online stores.
I believe this part is only on cars with the automatic temperature control setting.

1388199 Genuine Volvo - Air Flap Actuator Solenoid Valve - Free Shipping

 

Can you be a bit more descriptive about where/how to access this? Do I come from under the glovebox? Or on top of it? I know where the air flap is under the cover for the wiper arm relay under the hood, but the solenoid I'm not sure.

I'd appreciate it. Still having the issue.

 

Remove the large panel under the glove box. It looked like he reached up to the left of the glove box just a little and the relay was right there in plain sight. I was looking from the drivers seat, leaning over the console trying to see exactly where it was. Look at the link that has a pic of it & you should be able to see it. It was a gold colored metal relay. He just pulled the vacuum lines off and brought it out. The crack was so small it was not noticeable to me until I looked very close. Anyway, it still works so far. Hope this helps.........

 

The problem for this condition is with a vacuum control unit located in the cabin on the front passenger side under the glove box. Remove the large cover beneath the glove box. You don't need to remove the glove box.
The vacuum control unit is located on the left side. It is about 3"x4" and looks like an electric gizmo with a plug array of wires on the left of it and rubber tubes coming out the top of it, although array of tubes might be hard to see.

My control unit seems to have a problem with the electrical connector on this vacuum control unit. I was able to get it working by jamming a piece of wood to wedge pressure against the electrical plug array. This is all temporary until I can find a replacement unit at the junkyard.
I have lived with this problem for several years and thanks to this forum, I have the answer!! Now I can keep this car for many more years and keep cool in the summer! Thanks Volvoforums!

 

I have vacuum but how can I tell if it is bad or if the actuator is bad? I can not see any bad solders but the actuator clicks when i wiggle around the plug. I can tell if the wiring is bad or what but I get no response from any hoes.

 

I’ve just sorted mine by doing the above the green block of wires has movement so I cable tied it around the gold unit tightened it completely now vents work fully even on acceleration thanks for the advice 😃