348 ac compressor not turning on

If you did an engine out you might remember seeing back by the compressor a single wire going to the compressor clutch. It has a connector fairly close to the compressor. If you can find that disconnect it, then attach a wire to a 12 volt + source and with the other end of the wire touch the wire coming out of the compressor clutch. You should hear a click as the clutch activates. If the engine is running, the compressor will start spinning. If that works (if the engine is running, don't let the compressor spin for more than a few seconds) but it won't come on with the dash A/C. button, then find the dryer unit up under the passenger side little hatch in the from trunk ( black cylindrical thing with 2 wires coming out of the top) unplug the plug going into the top, and use a piece wire to short across the plug's 2 wires. Now try hitting the A/C button. If it compressor clicks on now ( with that wire in the back reconnected), it means you are low on refrigerant. If nothing happens, wiggle the plug going into the back of the control unit. If that fails, break out the wiring diagram and multimeter and get to work.

 

Carrying on from what Paul said, the quickest and easiest thing to do is put an a/c manifold gauge set on the and see if you actually have any charge in the system.

If you do, then it could be a number of things.

Fuse, bad earth, wiring issue, pressure switch or the a/c clutch is open circuit.

I just repaired my a/c in my 348 after 4-5 years. I had a melted fuse, no charge in the system and also an a/c clutch with an open circuit.

The front seal was leaking on the compressor, but that was not the original problem.

12 months ago I went to try and fix the a/c system because it stopped working 4-5 years ago. I put a gauge set on it and the system was full of charge.

I checked the pressure switch, had power to it. The a/c panel was all lit up and working fine at the time and I checked for power at the a/c clutch and there was 12v there when turning the a/c button on and off. Everything was spot on so straight away I thought the a/c clutch was open circuit.

But I didn't have time to replace the a/c compressor 12 months ago, so I left it be.

A few weeks ago the Brother and I decided to sort it once and for all. We put some gauges on it and guess what, no charge in the system. Obviously leaked out over the last 12 months.

**They always say you should use your a/c in ANY car at least for 5 mins, once a day to keep the seals soft and lubricated, definitely do because my compressor seal failed because I didn't use it. Clutch was stuffed anyway, but still use the a/c gents**

That melted fuse only just happened recently, so fixed that properly, filled the system with a little a/c refrigerant and noticed the front seal on the compressor was leaking.

Either way the compressor was coming out to be replaced. Once it was out, we checked with a multi-meter and I was correct, the coil was open circuit.

I noticed the old in the system was yuk in colour and smell, so we flushed it as best we could and added new oil. Also added some green dye into the system so next time a leak will become more obvious.

We fit a new compressor and drier, replaced all the orings and pulled a vac for 16hrs. Then we left it sit for 24hrs to see if it held vac to ensure there were no other leaks.

Was absolutely perfect! Charged it up and the a/c is the coldest a/c you will ever see in your life!!!

Anyone whom says the a/c in a 348 is average, they need to come and see Pap to have it fixed properly.

The a/c gets that cold, I turn it off while driving. I always have it set to LO on the display and we got 1.8c vent temps when we tested the a/c after the repair.

VERY cold and I am VERY happy!

Here are some random pics we took along the way.
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A couple of comments that may or not apply to your situation:

1- a good idea to find out why all the fuses blowing. There is a reason for that.
2-R134 oil is not compatible with r12 oil.
3- did you change to a "r134 compatible" receiver dryer? The R12 dessicant breaks down and can clog system in the presence of 134.

 

Without looking at a wiring diagram, I'm guessing that one pair of connectors is for the condenser fan switch and the other pair is the low pressure safety switch that protects the compressor. If that's the case, jumping the second pair of connectors should allow the compressor clutch to engage when the A/C system is switched on.

If you bypass the low pressure switch and the compressor does not engage the simplest thing to do would probably be to check for power at the clutch itself. If you have +12VDC at the clutch connection then the clutch itself has failed, if not it's time to get out the wiring diagram (ugh).

It does make sense to bypass the low pressure switch while testing voltages since it's possible that the system is low on refrigerant (or the low pressure switch has failed) at the same time that another problem has occurred.

Good luck and please let us know what you find.

 

You ran a test light from +12VDC to the wire coming out of the clutch? If so, all that tells you is that you have continuity in the windings inside the clutch, which you should. However, the clutch could be shorted. You would need to run a jumper from +12VDC to the clutch wire to test the clutch further. Either the clutch will engage or the jumper will get hot, indicating a short inside the clutch itself.

 

You're on the right track, but check for refrigerant in the system before you get under it man.

The a/c clutch won't kick in if it's low on charge don't forget.

First thing you do in any a/c system diagnosis, put some gauges on it.

 

Sorry, you're right there are more than 2 wires there. if the condenser fan motor came on, you probably connected the green to the blue/white wire. The green is the signal coming in, and the blue/white is the wire going out to the condenser fan. Try connecting the green to ( it's tough to make out the color code letters on the wiring diagram, so this may or may not be correct) the green/black wire. That's the one to the compressor clutch.
The fact that the condenser fan came on when you shorted across those wires, but not when you hit the A/C button is suspicious that the switch was off because the pressure in the pipes is too low i.e. low on refrigerant. Could also be a bad switch too. At least if you do the test above and the compressor clutch clicks on, you'll know that is functioning properly.

 

Sorry, I made my last post an hour ago but didn't send it till now.

You can check with a multi-meter using the OHM's setting on it.

If you jump 12v to it and you can't hear it click in, then it sounds like the clutch is open circuit mate.

The clutch will "kick in" if you put 12v to it yourself with a jump wire.

Mine had 12v to it with the ignition on, having a friend switch the a/c button on and off.

No "kick in" from the clutch itself, so I thought the a/c clutch was open circuit.

12 months later we removed the compressor and found I was correct.

You have gone the wrong way about it diagnosing it, but the end result will still be the same.

Check the a/c charge in the system, check fuses/relays, check the pressure switch, check for 12v power switching on and off at the compressor.

That's the order you would normally diagnose an a/c system in.

You still don't know if you have any refrigerant in the system? If the system pressure is low, the low pressure switch will not allow the system to turn on basically. This saves damaging the compressor.

Just because the system is 12 months old doesn't mean that you haven't got a leak somewhere in the system and lost your refrigerant. They could have pinched an o-ring at the time, left a loose fitting, hoses might be leaking etc. Anything can happen over the course of 12 months.
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No worries mate, looking forward to hearing from you.

 

Have you had time to look at this issue again?

 

Cool man, no worries.

 

How did you survive for 4-5 years with no a/c in your climate? My a/c isn't working, but in Scotland it doesn't get much above 20C very often so it's not really a problem.

 

Ugh. If the compressor grenaded internally it probably shot shrapnel into the lines. If you see any evidence whatsoever of metal in the compressor fittings or hoses you'll need to flush them out of the system before installing another compressor, lest that one grenade as well. From the sounds of it, the system might very well have been low on oil, so make certain to add the amount specified by the compressor manufacturer. Unless otherwise instructed by the compressor builder, use polyol ester oil, not PAG oil, since your system was originally filled with R12.

And you may as well change the drier while you're at it since they're apparently cheap online. There's a part number in the interchange sticky at the top of the page. Replace any O rings and Schraeder valves that are easy to access at the same time, since there's no way to be certain where the leak was.

BTW, if you live in a warm and/or humid climate, now is a good time to contemplate going back to R12.

Good luck and let us know how it all shakes out.

 

The "bang" could have been a hydraulic lock of the compressor. This can happen if the expansion valve is blocked or seized in the closed position and is recognised by the gauge on the low side reading very low (or even going to vacuum) when tested with sufficient charge of the system.

If this was the case, there might have been no damage to the compressor (just the belt). You can first check whether you can rotate the compressor by hand (try to turn the clutch plate at the face of the pulley). If it turns without feeling any hard stops but just springing from compression, I would release all gas and see if the compressor rotor can then be turned by hand fairly easily. If yes, I would next replace the expansion valve and try the system again.

 

Lol, I barely drive my car Ian so it's not a problem.

In that 5 years, I probably drove the car 30 times for 20 mins each I reckon.

I have just driven around 1000 km's over the last 4 weeks. The most I have driven my car in many many years.

The more I drive it, the better it gets.

I just fixed the a/c, sorted out a rusted out coolant header tank and about to repair my steering rack.

All the little things that have been buggered for years, finally have some time to get onto them.

 

The importance of putting gauges on the a/c system to see what the pressures are doing before you do ANYTHING else.

**Everyone remember this**

You have two issues here man.

You obviously have a leak in the system and you now have a compressor that's seized.

Remove the compressor and go from there. Let us know what you find.

I would try and replace it with a new one, but see what you can find.

Also replace the drier and orings as already mentioned.