A/C problem

[A55wanderer]

Having A/c problem. No A/c. System has been evacuated, vacuumed and recharged. Replaced thermistor and relay. Hot wired compressor to ensure clutch engagement and compressor comes on but no cold air. Checked blend door and it moves from hot to cold but still no compressor when you turn it on or turn the defrost on.
Any ideas

[elwesso]

Post up your low side and high side pressures.. That will help determine if the compressor is worn out or other possible causes..

Does the compressor come on when you turn it on normally through the climate control, or does it only come on when you force it on?

[A55wanderer]

Only when I force it on. And even then, the low side line stays warm. Leaning towards the expansion valve

[elwesso]

I could be wrong, but I don't think expansion valves fail too often on vehicles.. The only way you'd really be able to tell is to get in there and see what the temperature difference between the inlet and outlet of the expansion valve is. If the low side service port (which is between the evaporator outlet and compressor) is warm, that means that the expansion valve is not open enough or it's clogged. If that's the case I would expect to see low side pressure to be lower than you expect, and probably see the expansion valve itself be iced over and maybe a small part of the evaporator iced over.

[A55wanderer]

Both high and low side lines are hot with the compressor running and a fan in front of the condenser. I don't have a set of gauges and therefore can't tell you the pressures. I'm running on a hit and miss thing here.
It all started after I had the motor replaced. Was working great til then.

[elwesso]

Is it possible that since you vacuumed it you didn't get all the air out? If the system was open, did you replace the accumulator/filter-drier? Any time the system is open that needs to be replaced. If you didn't pull it down far enough and you still had air in the system it could cause this. Also, the oil in the compressor will absorb moisture, and if it wasn't sealed up real good when you took the engine out, it can take a real long time to vacuum out all the moisture out of the system (I'd let it sit on vacuum for a few hours minimum)..

Otherwise it could be really overcharged... If you splash water on the condenser with the compressor running and it works for a little bit after splashing water on it, you could be overcharged.

[A55wanderer]

I'll give that a try. Ty