I am trying to diagnose the A/C system of a 94/940 NA. When repaired 3 years ago they replaced the orifice valve and it blew cold for about a year then slowly began losing effectiveness over a few months until all cooling was lost. The compressor will come on and feeling along the high pressure line from the condenser to the firewall it is heated until the fitting where I assume the fixed orifice valve is and then is markedly cold through the firewall. The air temperature blowing from the vents does not change temperature with the a/c on. I notice no temperature difference of the return line from the firewall to the dryer from ambient. Does this possibly point to an evaporator problem if I cannot get any change in the vent air temp when it appears there is something cold flowing through he line?

Dirk
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Dirk Story