93 Q45 AC question

[Americain]

My 93 Q45 has been converted from R-12 to an R134 system and has been working fine for the last 2 years. Suddenly the system wouldn't cool at all. If you turn it on "AUTO" and turn the temp up to 85 degrees it will blow hot air as it's supposed to. Then you turn it down and as the temp passes 73-74 degrees the blower motor slows down then it gets faster as you approach 65 degrees but it's not getting colder, it's actually warm air. The pressure seems fine, about 43 lbs. approx. and the only thing I can find in the fuse box is a relay that's an unknown quantity. From other threads on this subject I've noticed that the hi-low switch might be suspect so at the moment I'm thinking hi-low switch but I'm not sure. Any more ideas guys? Thanks in advance.

[Q45tech]

Unfortunately, there are full and various grades of partial conversions.

Between r12 and r134a the only common component is the evaporator.The FSM and addendum points out that a perfect conversion will still result in a 3.8F increased center vent temperature or 88% vs 100%.

Assumming the conversion replaced the receiver dryer and sensors you should be able to use the numbers in 1994 FSM for pressures. How old is compressor?