Hello,

Your symptoms could be due to refrigerant overcharge. When the engine was turned off after some driving the engine heat heats up the refrigerant in the pipes and condenser within the engine compartment (heat soak) making the system pressure high. This shouldn't occur with a correct charge unless a very very hot weather.

High pressure turns off the violet pressostat at the front of the condenser. The violet pressostat determines the high safety limit for the system whereas the pressostat on the accumulator determines the low safety limit for the system. The other two pressostats (grey and brown) are meant to turn the radiator fan at low speed and high speed respectively if the system pressure gets very very high.

This means that your violet pressostat is working normally as it should. The thing to check is was the correct refrigerant weight charged into the system? It should be 950gm or 33.5oz. Yes its that precise especially in an orifice tube system. Orifice tube systems are critically charged. It is not self adjusting as in thermostatic expansion valve (TXV) system, hence the need for proper charge. If the refrigerant was charged only by reading manifold gauge pressure then that's where the error could have occurred. Charging by this method must take the ambient temp into account as the system pressure changes with ambient temp, especially in R134a system. Because of so many variables to account for when using this method, it is better only to charge by weight.

You may try to bypass the violet pressostat but only do it for a short while as the system may be overcharged. Locate it in front of the condenser. You may have to lie underneath the front bumper for a while. The electrical connections to the pressostats are keyed so that they are not easily interchangeable with one another. Put a paper clip across the connection. If the compressor works then your system is overcharged.

Hope this helps.

Amarin.