AC Trouble Shoot.. where to start?

My AC was working well last summer. Winter came so obviously wasn't being used. Summer showed up and no more AC. Upon inspection I found that the AC discharge line (from condenser to compressor) had vibrated against the body and caused a hole, obviously allowing all refrigerant to escape.

I replaced this line and tested vacuum pressure. Held for well over and hour. Continued to applied vacuum. Attached coolant. Opened coolant and sent into system. Truck running, AC button and fan on. Air blowing. AC light at dash steady.

But the compressor won't kick on.

I have done a refill like this before and after a moment or two the pressure builds to a point the the compressor will engage and suck the coolant into the system. But this time nothing.

My question is where would one start to trouble shoot? What might have failed when the line leaked? Could the compressor or a component been damaged trying to run the AC not realizing the refrigerant had leaked out?

Thanks.

 

Unplug the pressure switch, jump the terminals, and see if it comes on, might just be a failed pressure switch.

 

If you used those small cans of r134a with a can tap this may help cause it happened to me.
The top of the can where you screw in the can tap was modified a while back. ( don’t remember why). Some can taps won’t work unless you use the can tap adapter that they now sell to solve the problem. It’s a blue plastic part that you can get at automotive store. I kept jumping the compressor also until I discover this solution.

https://www.napaonline.com/en/p/BK_7653152

 

oil loss from the leak seized the compressor?

 

That's very interesting. Last time I worked on my AC everything was piercing cans style. So my tap would connect to my hose but the can of course would not open. I went back and purchased the correct valve for the newer self closing can... but are you saying this new tap doesn't flow enough through the old hose?

Meaning this NAPA part allowing old taps to work on new cans might increase flow of refrigerant?

 

Not saying this is or is not possible, but wouldn't a seized compressor still allow the clutch to cycle between on and off?

 

No, alls I was saying was make sure you are using the correct tap for your r134a can.

 

If the pressure switch jump @Dm93 suggest doesn't do anything, check for power at the compressor wire.

 

If the compressor was commanded on by the A/C Amplifier and not turning the A/C light would be flashing.
The fact that the light isn't flashing tells me it's not commanding the compressor on.

The A/C Amplifier has several inputs it uses to determine when to turn the clutch on.
The pressure switch and Evaporator Temperature sensor are the main inputs.
The temp sensors rarely fail so makes sense to check the pressure switch first.
The switch should be closed once system pressure is above about 30 psi and under about 450 psi.

 

I connected the wires of the pressure switch, and compressor comes on. Although I will say the compressor came on with a jolt, felt like engine might stall for a second.

So this seems to point to my pressure switch being bad. Is there a good way to test the switch further to confirm?

Also, I assume once the line was cut and refrigerant escaped (probably rapidly) the pressure switch kept the compressor from turning on. Would this mean most of the lubrication oil in the sytem would have remained in the system?

I guess I am asking is how does one determine if oil is needed to be added at this point.

Thanks.

 

See what the high side pressure is, if it's above about 30 and below about 450 and the switch is still open then the switch is bad.
Be aware the refrigerant must be removed from the system to replace the switch as it has no isolation valve under it like many pressure switches on A/C systems do.

It's impossible to know how much oil came out, most of it should stay in the compressor but a sudden loss of refrigerant could have shot some oil out with it.
Probably would hurt to add an ounce of oil but I would put anymore than that.

 

So, I got it all sorted out.. kind of.

I went ahead and installed a new compressor. With everything apart I figured I might as well. Vacuum test past (held for 1 hour, no leaks). Ran vac for another 45 minutes plus. Took in one full can of R34a and as best as I could measure 10oz from can two, bringing me to 22oz overall. Air was blowing cool through the dash at time work was done. All vents.

But now after driving it a bit I definitely feel like it is not blowing cold as it could be. Strangely the DS vent is definitely colder than the rest. In fact it seems to blow progressively warmer as the vents move towards the passenger side.

What are the symptoms of too much or too little refrigerant? That's the only thing I feel could have been done wrong at this point.