Good A/C clutch+power+freon = A/C no worky!

[briwayjones]

After this winter the A/C on my 2000 wasn't working anymore. I investigated it some today. I jumped the compressor clutch and it is engaging. I checked the plug with a multi-meter and it is getting power. It has full freon. I checked the fuse and it's good. I don't know about the relay. But I would assume that if you're getting power at the plug and it's trying to turn the A/C clutch on then all fuses, relays and the low pressure switch would be good? What else could be wrong.

 

[briwayjones]

bump

 

[Maniak]

Are you saying that when you put 12v and ground to the compressor that it engages? That means Good a/c clutch.

If you put the plug back in the compressor and then use the normal switches to turn on the a/c do you have 12v when you measure across the 2 connections on the plug?

If so then the compressor is being told to turn on and that means that the power isn't getting from the plug to the clutch so I'd expect it to be a bad connector. You can always jump from the plug to the compressor (while making sure you are seeing the power and ground getting to the clutch)...

I am assuming that your explorer uses something like the fs10 compressor which has a ground/power wire going to the clutch.

~Mark

 

[briwayjones]

Yeah when I put 12V and ground to the compressor the clutch engages. With a multi-meter I'm getting power to the plug on the harness with the A/C switches turned on. The freon is also good.

If you put the plug back in the compressor and then use the normal switches to turn on the a/c do you have 12v when you measure across the 2 connections on the plug?

How do I measure across the two connections on the plug if it's plugged back in to the compressor?

If so then the compressor is being told to turn on and that means that the power isn't getting from the plug to the clutch so I'd expect it to be a bad connector. You can always jump from the plug to the compressor (while making sure you are seeing the power and ground getting to the clutch)...

I don't think I follow you here on where to jump to and from.

 

[Maniak]

You have to backprobe the connector. Take a solid wire or paper clip or something and shove it in the back of the connector where the wire goes into the connector.

Here is a kit you can buy but you should get the idea just by looking at what is in the kit.. http://www.amazon.com/Thexton-THE490-Back-Probe-Kit/dp/B000OCIX7Q.

We are just trying to prove that there is power/ground when it's connected... but it's not as important...

However, using logic (not proving it), you can find power/ground at the connector AND we know when we manually put power/ground to the compressor, it engages. Then we know that the power/ground isn't making it from the connector to the clutch.

To prove this....
We want to run out own wires from the connector where we know we have power and ground to the compressor. If that works (and you can still measure the power/ground on your wires) then we know the issue is the connector must be bad. To run your own wires you will probably need some alligator connector/test leads (http://www.amazon.com/SE-TL10-10-Piece-Alligator-Clips/dp/B0002KRABU). IIRC you can put the alligator connector onto the the spade connectors on the compressor. Now clip the other end of the alligator/wire to a piece of wire and shove that piece of wire into the connector. When you have all that wires up you should be able to use your meter to check that you still have power/ground at the compressor since now you can get your leads in there.

hopefully that rambling made sense..

~Mark

 

[briwayjones]

hopefully that rambling made sense..

~Mark

Okay I think I'm starting to get it now. Just to be clear, I may not have been using good terminology. I tested the connector by sticking the negative probe on the multi-meter into the negative/ground on the connector and the positive probe into the power side of the connector. And it read as 12v coming through.

But you're saying that even though I got that reading from the connector it might be bad and when I plug it in to the compressor the power may not be making it to the compressor?

So to test it plug some kind of small wire, like a paper clip into both sides of the connector. Test them to make sure that I'm getting voltage on them? Then connect to them with leads with alligator clips or something similar and then connect them to the plug on the compressor? And then see if the compressor engages? If it does then we know there is some kind of problem with the connector itself?

 

[Maniak]

Exactly... Now you got it..

~Mark

 

[briwayjones]

Exactly... Now you got it..

~Mark

Well, I tested the connector again like I did before. And tried testing it using paperclips/safety pins to get in the connector better. Now I'm not getting any power at the connector. So I don't know what's going on. The only difference than before is the freon was in the low side of the normal range so I added some and got it up to the high side of the normal range. After I tested it initially. Could there be too much freon and it's not telling the compressor not to come on?

 

[Maniak]

Well, if you aren't getting power at the connector now, that would explain why it isn't turning on..

Time to follow things backwards.

In other words, you need to find how far the 12v gets. IIRC, your system has a low pressure cutoff and a high pressure cut off BUT the high pressure cutoff is on the high side and you will only reach the cutoff pressure with the system running (e.g. It's somewhere around 350 psi).

So, find the low pressure cut off switch and see if you have power on both sides of the switch. If it thinks your pressure is too low or the switch is bad you will find 12v on 1 side and not the other...

If you find no 12v on either side then you need to keep working backwards. I don't know if your system has a WOT relay (cuts power to the a/c when you are WOT) but if you do that is another place that could be bad.

However, it's possible it's your a/c/climate control head that is having all the issues.

Overall, Right now you know there is no 12v at the compressor so you just need to find where it's getting stopped.

~Mark

 

[briwayjones]

So, find the low pressure cut off switch and see if you have power on both sides of the switch. If it thinks your pressure is too low or the switch is bad you will find 12v on 1 side and not the other...

What does the switch look like? Or any tips on finding it? I have seen it referenced a lot in threads on here but haven't found any pictures or anything.

 

[briwayjones]

Okay, dragging this thread back up. This winter I noticed something. That when using the defrost settings the compressor kicks on like it normally would and is supposed too. But when using the A.C. the compressor does not come on.

 

[SoHK_alumni]

Does it have the automatic climate/temp control?

The a/c system really only has 6 electric components.

In-cabin control, fuse for power, relay, engine pcm, low pressure switch and high pressure switch.

From your description, I'd be most suspicious of the in cabin controls, particularly if you've got the automatic system.

 

[SoHK_alumni]

Does it have the automatic climate/temp control?

The a/c system really only has 6 electric components.

In-cabin control, fuse for power, relay, engine pcm, low pressure switch and high pressure switch.

From your description, I'd be most suspicious of the in cabin controls, particularly if you've got the automatic system.

 

[briwayjones]

Does it have the automatic climate/temp control?

Nope, no automatic control, just the regular.

 

[SoHK_alumni]

Still, if it all works correctly on Defrost, that pretty well verifies the rest of the system so the in-cabin control is still the prime suspect.

 

[briwayjones]

Still, if it all works correctly on Defrost, that pretty well verifies the rest of the system so the in-cabin control is still the prime suspect.

So in other words the switch control panel?