Based on the earlier advice, I gave myself a few days to test it out before sholdering the aircon relay connection in the control unit as suggested by some. Besides occasional non activation of the compressor, today I encountered something very strange. The compressor was working/spinning when I activated the aircon but 5 mins later except for blower working the compressor is dead (not spinning). Now, how is it possible?? After a while when I restart and on the aircon everything was ok (compressor spinning but cool air slightly weaker).

Compressor is new. Recently, refill and check no leak. Then what? Could it be the A/c pressure switch (grey, brown voilet)? Need to change? What is pressostat and where is it located? Or is it due to the connector/switch to the drier? Help please. Cannot afford to change all.

Sounds like you need to solder the connection on the control unit. When the connection is bad, the compressor does not run.

Soldering the connection to the control unit transmit current to activate the compressor. But, I encountered the compressor clutch spinning but stopped after 5 mins. Precisely, this explains why I am still quite lost.

If the connection is semi-bad, it will sometimes make enough of a connection to start or keep the compressor engaged. Sometimes it will not --- temperature of the connection will change and thus change the conductivity of the connection. If it heats up, it could lose the connection and thus the compressor dis-engages.

Tks Philip. Took your advice seriously including print out from FAQ700/900. Consulted 2 mechanics who show me some dismantle air control units and explained that it is due to the relay. Both advise by pass method. It seems that this is the only way they know how to fix in Asia. (I am just concerned if I insist soldering as recomended by FAQ700/900 and it still does not function properly I might have to pay again labor cost to have a by pass. If I go ahead with the by pass the mechanics who assured me of success rate, my other concern is the connectivity of current as mentioned by you. I am delaying fixing it because the air con still working fine except on rare occasions, the compressor suddenly stop but if I repeat the on and off switch a couple of times, the compressor came back again. Any experts out there on this issue?

Tks Philip. Took your advice seriously including print out from FAQ700/900. Consulted 2 mechanics who show me some dismantle air control units and explained that it is due to the relay. Both advise by pass method. It seems that this is the only way they know how to fix in Asia. (I am just concerned if I insist soldering as recomended by FAQ700/900 and it still does not function properly I might have to pay again labor cost to have a by pass. If I go ahead with the by pass the mechanics who assured me of success rate, my other concern is the connectivity of current as mentioned by you. I am delaying fixing it because the air con still working fine except on rare occasions, the compressor suddenly stop but if I repeat the on and off switch a couple of times, the compressor came back again. Any experts out there on this issue?

When I bought my 94 940 last year, the previous owner had installed the by-pass solution. The problem was that it would keep running, never cycle and ice-up, which caused decreaed cooling and had the real probablity of damaging the compressor. The first thing I did was to rip out the by-pass and solder the controller.

Hi,

Tks you for your advice. I agree with your comments and after exploring various options, I decided to send my car to a mechanics about 30miles away just to fix it. An experienced old hand who took out the control unit and dismantled it to show me the connection. Apparently, everything looks ok especially the soldering is cleaned and shinning. He suspects maybe other problems. (3 other relays just in front of the condenser/radiator.) Anyway, a quick fix was like what you suggested - - solder the relay joint. So far, ok. Have to really know after a few days since the problem is erractic. Just hope it is not the relay itself which is 1 of the other possibilities.