A/C clutch not engaging

[Jasen]

It worked well before I left for Hawaii 2 years ago, when I came back last year it didn't so I figured I had a small leak and it just leaked away while I was gone.

I charged it today and it was only a couple pounds low, then I noticed the clutch wasn't engaging. It spins by hand with resistance and has no wobble or grinding noises.
I hooked my meter up to the low pass side? (plug up on the collector) and got 12.6 V, I checked the high pass plug on the top of the compressor and got point13 V, then it started jumping all over between .5 -.11V
I jumped the low pass side (@ collector) and it kicks on, so that's just a bad low pass switch, right?

Looking at the LAP site for prices, it looks like the switch on the collector is actually a comp. cycle switch?

SAFETY SIDE BAR:

I used some 22g speaker wire to make a long jumper lead from the compressor plug, then hooked my meter to that to keep my hands away from moving pulley's, belts and fans.

[Jasen]

This is the plug I jumped, is it the comp. cycle or low pass switch

[paintdrying]

I heard it is in the 40's up there in Seattle. I would say, just not to worry about it.

[Jasen]

I's 70+ at 1:45, we don't get our max temps till late in the day. Next month is usually when we start getting into the 90's. All them's people that have been @100-115° can have it, this is one reason I stay here.

[paintdrying]

If it were not for that heavy traffic I would be there.

[Big_kid]

Yes, that's the low pressure switch.

[Lumpy]

1845 hrs local time Phoenix -


In 2-3 weeks we'll start having overnight lows of 100+ for a week or two.


Lump

[paintdrying]

Wow. I almost want to ask if those temps were photo shopped. Man that is some serious heat.

[Jasen]

Yes, that's the low pressure switch.

So when I jump the LP switch and the clutch engages it should just be a bad switch then?

This is my confusion.

This clutch cycle switch looks like whats on the accumulator, I jumped the plug to it and the clutch engaged.



But this is a low pressure switch

[chevymaher]

If it on the accumulator it is the low pressure switch. First switch shown is what mine uses on the accumulator. Replace it problem solved.

Second switch shown looks like the high pressure switch which goes in the back of the compressor to me.

[Jasen]

Thanx for clearing that up Randy

Maybe Oreilly's have them listed wrong on their web site.

[Jasen]

So when I go to R&R the switch, it's going to vent all my refrigerant isn't it, which also means I'll have air in the system, and I don't have the equipment to purge the air, plus I don't think the 22 oz can of R134 is going to be enough to fill the system.

Whats an A/C service cost these days? It's probably a flat rate regardless of how much 134 they add.

[chevymaher]

When you change the switch it will vent it all out. I use a tire schrader valve tool. Loosen the schrader valve in the accumulator so it leaks slowly. That way you dont loose the refrigerant oil. The green stuff.
When it really low just switch the switches fast. You wont get anything in the system. Only travel is out. Nothing getting in for a few minutes. The refrigerant is still boiling out in the system and coming out the hole.

You will be fine. It takes 3 small cans to fill it after your done if you only have front air.

[Leeann_93]

It has a schrader valve. When I replaced mine on the Bravada, it did NOT leak out except a small hiss when I removed the old and installed the new.

[Jasen]

Thanx yous folkses.

I decided to just go for it. I jumper the LP switch to engage the clutch and ended up dumping a whole 22oz can in it. I left the bottle hooked up for about 5 mins and watched it cycle. The green on the refer can gauge is 25-55 PSI. The cycle kicked off at 53-54 PSI and back on at 23-24 PSI every time.
It's blowing cold now, but we will see. I could have a micro leak and after sitting for a year I could have lost enough to drop below the LP switch threshold We will see.

[CharlieV]

I'm having a problem with my A/C. I bought a can of A/C PRO refrigerant that comes with that gauge that tells you how much refrigerant you need to add. When I went to charge it, it said I was over-full, and when I turned on my A/C the compressor didn't appear as though it was turning. As far as I know, all the electrical wiring to the A/C is hooked up, although there is one plug that doesn't seem to have anywhere to plug into that I can see, not sure if it has anything to do with the A/C or not. Can't upload photos to A/S or Photobucket for some stupid reason and it's really frustrating me. Can anyone help?

[chevymaher]

The plug your seeing is a spare windshield washer bottle plug.

It will read overfull unless the van is running and the air conditioner is on.
There is a high side and low side pressure. You test and fill from the low pressure side.

Put it on max A/C with the fan on and see if the compressor starts.

[Jasen]

From my research today, the A/C clutch has to be engaged to charge it, you won't get a system pressure reading if the compressor isn't engaged, if it's to low on juice the clutch won't engage. This appears to have been my case. I unplugged the leads from the low pressure switch and jumped it to engage the clutch and then filled it. If the clutch doesn't engage once jumped, you may have a bad switch, don't charge it.
With engine running and A/C and fan at Max, juice hooked up and ready to go, unplug the lead and jump it with a piece of wire, paper clip, whatever and charge the system. Once done plug the leads back in and check that the clutch engages.

The low pressure switch as indicated by the arrow

[chevymaher]

If the system is just low/empty. Have the A/C on max.With engine running. Start putting in the refrigerant. Compressor will kick on and off. Just keep adding till it starts staying on, check pressure. Hold the can upside down to fill. You don't have to jump that switch. It will start when the pressure rises.

[paintdrying]

This whole leak thing is what worries me. Can a guy just fill a completely empty system with air to see if it will hold. I have rear air and the guy at oreillys tells me it will take two big cans to fill. They sell this repair kit for fifty dollars, comes with a uv light. you put the first can in, then look for leaks. So if it leaks you just lost one can.