Not all cars came equipped with the high-pressure valve. That's why the manual shows two different setups. It just never got completely updated. On later cars the high-pressure switch was located at the front of the car at the bottom fitting of the condenser. If you look on page M:18:19 you will find where the wiring diagram picks up the high pressure switch. It is basically spliced into the wiring (one wire) ahead of the low pressure switch. If your car does not have one, it is fairly straight forward to put one in. It is a good safety device especially with the R134 higher pressures. It is the low pressure switch mounted on the accumulator that cycles the clutch. There are two accumulator types. One, the early type, has the return at the bottom of the accumulator; the other newer type is higher up on the side. To switch to the later type, which is most certainly required unless you can find a NOS one somewhere, an adapter for the return hose is needed - or a hose modification or hose replacement. I've tried to figure out a rerouting but it is a waste of time. Generally you can thread the hoses down the frame if you a can get on a four-point lift and use a little ingenuity in how you angle things. I have replaced mine without loosening the body from the frame. Since it worked last summer then stopped - you put in a new charge and it worked for a while - you DO have a leak. I agree with other observations that it is probably the high side hose - but, did you check the condenser under pressure? They are notorious for springing leaks if the have been damaged by rocks, etc. Also, the evaporator can spring leaks because of corrosion on the outside of it. This damage can be caused by what I call "being put away wet". I like to run the fan at high speed of a few minutes before I put the D away for more than a few days because the moisture just sits there otherwise and does its damage. Also, the new seals are a must with R134 and not a bad idea with R12. What about the compressor shaft seal? Harold McElraft - 3354 (high and low pressure switches) --- In dmcnews@xxxxxxxxxxxxxxx, Michiel Böhmer <michiel.bohmer@xxxx> wrote: > Dear list-members, > > I'm lost here. I have AC troubles and I can't find my answers in the archive. I have had my system converted to 134a by a specialised company. (new compressor, new orrifice, new accumulator, flushed etc.) by the book I would say. It worked for over a year and then all of a sudden it stopped cooling after getting very cold.