My wife's 1992 960 SW no longer has AC or heat blowing from the 4 central outlets on the face of the dashboard. Plenty of hot and cold at the feet and some at the defroster but nowhere else regardless of the setting. This seems to have occured recently however she kept the heat going to just her feet throughout the winter. Am preparing to take this car on a long trip and need to have some climate control. Is this something that I can tackle myself or does it require excessive mechanical talent? Any suggestions would be greatly appreciated.

Agree with the previous posts, bt would recommend a disciplined approach going from easiest to hardest sources. I'm assuming you have the same basic ECC as my 1989 765 Tic.

First, there is a black and white check valve near the intake manifold that could be your problem. If the check function had failed, as many do, it would have caused normal ops of dampers only during periods of vacuum in intake manifold. Since this is not your sypmtom, it could have totally failed and may be closed.

Second, there is a vacuum solenoid manifold on the driver's side of the center console that can develop cold solder joints in the multipin connector. This will result in a default condition where all airflow goes to the feet and defrost outlets. (Similar to your problem) Once you gain access to this part, start the car, set the ECC to normal, and flex the connector. On mine, flexing the connector caused everything to start working correctly when in just the right position, clearly identifying the cause. Resoldering the joints has corrected the problem for 50 k miles without return.

Third, you can start thinking about tracing vacuum. You want to begin inide the firewall and verify you have vacuum into the cabin. Then follow the vacuum line into the car and verify at each component that you still have vacuum. This is a real PITA and takes alot of access under the dash. Some shops have an ultrasonic source they put into the vacuum lines under the hood and a detector they use inside the car to find the leaks. Save incredible amounts of labor hours but the tool isn't cheap.

Finally, and I doubt this is your problem, you can verify your vacuum motors (aka: dampers) are functioning. I don't think this is your problem, but it's possible you have a very bad leak through one of them.

Good luck. I found on mine that once I put the time into getting it thoroughly checked out and running well, it is a pretty reliable system.

HTH,

someguyfromMaryland

Just went through this with mine. FAQ is indeed place to look. If you don't see apparant main vac hose leak, try detaching and plugging small yellow vac line to servo. To do this, remove knee panel under dash on drivers side with two half turn plastic retainers, look on right side just behine console and note round disk shaped vacuum server toward rear (there is another toward front of car next to it) with small yellow and (I think) blue vac line. There is a loop on the fitting end to hold it on the 90 degree fitting of the servo. Flip this loop toward the line and pull off. Use something to block the yellow line (I put in a small screw, careful not to stretch or damage it). My dash air starting working again.

Guys on the board told me it may diminish air at my feet, but beats I can compromise for not having to spend 4 hours of labor to replace servo.

Gary

I agree that this is likely a failure of vacuum to get either to the control unit or out of the control unit. This is the default position of the vent system. Check for a small vacuum line from the intake to the firewall.
This hose may be split or has come off.
Also your car may have diagnostics in the climate control unit. There may be a blinking indicator light (like the blue AC light) if it has an internal fault.

Also look to make sure you don't have a blown fuse. Check the fuse cover for "AC" or "Climate Control" fuses.

Good luck.
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 229K, 88 744GLE- 218K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 88 245DL, 246K

This sounds like a vacuum leak in the heating and cooling duct network of hoses or vacuum motors. Check the FAQ as I believe this is covered. You want to check the vac. lines from the engine area feeding through the firewall to the interior first. Also check if this is only on acceleration or deceleration.

dick