Originally posted by gsjohnson
Do both units quit at the same time?
If it was a fan or condenser problem your high side pressure would be 300 psi in a very short time.
with only 175 at 2000 rpm you can rule that out.
Check to see if you can feel which evaporator is messing up.
You might be able to feel a difference on suction line where they tee together.
I believe the front has a orifice tube and rear has a txv.
The orifice tube should be right at the connection of the condenser, feel it to see if there is a temp drop.
Then recover vac and recharge.
If it still does it I am suspecting a weak compressor or bad end on orifice tube.
I would put a new tube in it while the 134a was out of it.
That might be a cheap 5.00 fix if your lucky.
As for the high pressure due to two units I dont believe that would cause it. I work on semi with front air and bunk air all the time with same set up as yours and depending on the outside temp they will run 25 to 40 on the low side.
Let us know what you find out.