Heating Air Con

[Blue Skies]

I noticed that my air con was not working after switching it on , first time for a while, on a motorway journey last week. I also noticed that the face level vents had no air coming from them. The blower motor seemed to be working at all speeds, but no air conditioning and no air from face vents and vents under dash. Air was coming from windscren vents. I do not know if the AC not working and the face level vents not working are related. Any ideas.

I have a 1998 940LPT Celebration.

Cheers

I haven't got the same car as you, but some things are likely to be pretty standard.

First off, the control unit for the aircon / etc. If your one is an electronic module behind all the dials and switches then if this has gone wrong then maybe signals are not being sent to the servos to adjust the direction of air to the face vents.

Second, same thing could be causing electrical faults meaning aircon is physically not being turned on. Start engine, turn on the air, and get out and have a look at the compressor in the engine bay. Is it turning? If not, aircon not working.

Or, if that's a bit tricky to see, when you put on the air do you hear a noise like something starting up? Or even feel power drop a little? If no signs, could be it is doing nothing which could all be tied in with the climate control module failure of some sort. Could be an electronic or electomechanical problem. If it seems the aircon is on, could be refigerant level needs topping up or other fault.

If you have an entirely manual system for redirecting the air (which would probably have only say 4 positions on the dial instead of many) then the problems are likely unrelated and the fault in air direction could be a knackered control lever or something like that.

Some possibilities to thing about maybe.

Pete

[TheJoyOfSix]

Originally Posted by Blue Skies

I also noticed that the face level vents had no air coming from them. The blower motor seemed to be working at all speeds, but no air conditioning and no air from face vents and vents under dash. Air was coming from windscren vents.

If (as is likely at that age) you have the vacuum operated flapper system for the vents then a possible cause for the above symptoms is the solenoid valve block that directs the suction to the various flappers. It is a approx 2.5"x2"x0.75" box brass in colour with all the vacuum pipes connected to the top of it and an electrical plug on the front left side.
If you take the passenger side trim panel off and look up at the heater system you'll find this block on the right hand side roughly where the passengers right knee would be. With the engine running and selecting air to anywhere but floor/windscreen try wiggling the electrical connector. If the air is sent to the selected vents then the chances are that the soldered connections on the block have deteriorated. i have had to remove the block and resolder the connections on 2 760's that I have had and 3 960's and a 940 that friends have had.