Compressor not turning on -- cooling box plug (1 Viewer)

[amw2320]

I am trying to resurrect an old-dead AC system. I replaced the compressor, drier, and expansion valve, and have flushed and vacuumed the system.

Now I am trying to charge and I don't think the compressor is kicking in. The pressure is 70 on the low side, and still at vacuum on the high side from my previous vacuuming.

When putting the cooling box back in there was an extra plug above it which I cant see going to anything. Anyone know what this is?

Cooling box extra plug

• amw2320
• Aug 16, 2018

 

[amw2320]

Nevermind, pulled the glove box on my other FJ62, and the dangling plug is still there too.

Any idea on what I need to do to diagnose this? The AC fuse is fine. I'm running at 2000rpm to try an engage.

 

[amw2320]

Manually made the clutch engage by jumping a couple of pins from the amplifier cable, as shown by TrickyT. Still no change in my gauges. Weird.

 

[flintknapper]

I am trying to resurrect an old-dead AC system. I replaced the compressor, drier, and expansion valve, and have flushed and vacuumed the system.

What exactly did you 'flush' and with what? Did the original compressor fail? You kept the old condenser and evaporator? Please say you didn't flush those.

Now I am trying to charge and I don't think the compressor is kicking in.

It either is or isn't. Simply looking under the hood (A/C on) will tell you if the clutch is engaging.

The pressure is 70 on the low side, and still at vacuum on the high side from my previous vacuuming.

70 psi is too high for low side pressure and it isn't possible for you to have pressure on the low side and vacuum on the high side unless there is 100 percent blockage somewhere separating the two circuits. I am assuming you are using manifold gauges and they are in good working order?

^^^^^ expand for replies

We need more information and I have a LOT of questions for you.

 

[3_puppies]

The pressure is 70 on the low side, and still at vacuum on the high side from my previous vacuuming.

I don't understand the above statement.
not an expert on this, but usually the system will balance out and have the same pressure on both sides. you having vacumn on 1 side and pressure on the other isn't right and the low pressure switch is most likely not activating as you still have vacumn.

 

[flintknapper]

I don't understand the above statement.
not an expert on this, but usually the system will balance out and have the same pressure on both sides.

When not running the system will seek to balance out....this is known as the 'static pressure' and depending upon the ambient temperature a low side reading could well be 70-90° F. BUT...this is NOT how we check the system pressure.

you having vacumn on 1 side and pressure on the other isn't right

Correct. The only way for this to happen is for there to be a complete obstruction in the system...which would separate the two circuits. OR....the OP's manifold gauge or lines are at fault. It's quite possible to that the high side hose (for the manifold gauge) is not getting a pressure flow (shrader valve not depressed on A/C high side port, etc....).


and the low pressure switch is most likely not activating as you still have vacumn.

The low pressure switch does not influence Vacuum...it is not a 'valve' as many often think. It is a normally open/closed switch (depending upon how configured) that completes/interrupts the electrical circuit to the compressor clutch. So it isn't that.

^^^^^^ Expand for replies

We need a LOT more information, not the least of which would be the OP's experience and understanding of how to use the Manifold Gauges and recharge the system.

My suggestion for the OP at this juncture would be to insure that both service ports are open and not obstructed. He could do that by hooking the gauge set back up to the system and his vacuum pump, open the high side only and watch to see if the low side gauge begins to pump down. IF it does then we know the ports are open.

 

[amw2320]

My experience in working with AC systems is absolutely 0. I am a weekend tinkerer and this has definitely been one of my bigger projects. Flintknapper, I agree and think my issue is actually related to the manifold gauges and/or service ports. The adapters (amazon link) I put on did seemed to leave a bit of space between the schrader valves and the top of the adapter.

I thought I tested them by manually pressing on the schrader valves after after vacuuming and removing the guages and got a nice little hiss.

The last thing I did last night was disassembled the manifold guages then reinstalled them. Pressure read 0 on both sides.

I'm taking it into the little A/C shop down the road so they can check if I have everything installed correctly.

 

[flintknapper]

My experience in working with AC systems is absolutely 0. I am a weekend tinkerer and this has definitely been one of my bigger projects. Flintknapper, I agree and think my issue is actually related to the manifold gauges and/or service ports. The adapters (amazon link) I put on did seemed to leave a bit of space between the schrader valves and the top of the adapter.

I thought I tested them by manually pressing on the schrader valves after after vacuuming and removing the guages and got a nice little hiss.

The last thing I did last night was disassembled the manifold guages then reinstalled them. Pressure read 0 on both sides.

I'm taking it into the little A/C shop down the road so they can check if I have everything installed correctly.

Good deal. Please let us know if there is anything we can help with after you hear back from them.

 

[amw2320]

Looks like it was just a bad manifold guage (thanks Autozone). AC shop wasn't able to look at it, but I realized something was up when the pressure tubing open to air was able to hold a vacuum.

It's being re-vacuumed now, lets hope it holds pressure as well as when the tubes were plugged.