I just got a 2009 Z51 3LT, the AC worked on my way home, until I got on it, it cut off as it should, but when I slowed down it never came back on. It just blew hot air. What do Y'all think is going on? The first time it happened, I stopped, turned the car off and back on and it fixed it. The second time I wasn't so lucky.
Mods are MS4 and a Longtubes.

 

There is a good possibility you have a bad AC compressor relay. Swap it out with the one for the horn and give that a go.

This suggestion is one of many many things that could be wrong but its and easy one to test.

The ground for your compressor relay is through the low pressure switch.

 

Check the belt for tension.

 

Or, check the belt for being there...

 

You sure it is in Auto? I thought I had a similar problem today but it turns out I must have nudged a button other than auto when shifting out of park. I can imagine while banging through gears, something similar could happen. Just a thought.

 

Can confirm that the relay is not the issue. Switched the horn and compressor and it still wouldn't kick on. The belt tension is good and I have been clicking through between auto and manually selecting the temperature.

 

Could be low on charge if compressor won't kick on. You could briefly jump out the low pressure switch to see if compressor clutch pulls in.

 

Did the same with my M6. Very easy to do!

 

Agree. I would also check to see exactly what the pressure is. I would still think that once the pressures equalized that it would again kick on just as it does before you go throttling it.

One of the sensors may be faulty.

 

Not sure what diagnostic checks cost these days, but this one may be best to take somewhere and let them use all the tools at their disposal to find it. One can chase these kind of problems for days when trying to do so in your own garage.

 

Just figured it out! The pigtail that goes to the compressor is getting pushed out of the way by the AC line and keeping it from making a good connection to the compressor, Ill have to do something to the lines out of the way...

 

Good catch. Glad you saved yourself from a dealership.

 

But now the more I look at it, the more I think the pigtail is fine and its the connector on the compressor housing thats becoming intermittently disconnected, if thats the case, how would I go about fixing it?

 

That half of the connection is the clutch for the compressor. Its actually a electromagnet. that enegrgizes and engages the clutch.
A clutch replacement will be far less costly than a new compressor. They are damn expensive

 

First, you should look into the connector from the harness and ensure that the female terminals are not bent as if someone had stuffed a probe in them at some point. If they are you can buy a pin release tool from ebay and it will be an easy fix.


If those are good:

I would agree on a clutch replacement but if you are wanting to save money you could remove the compressor and get to the wiring at the female connector on the comp itself. You could either extend the wiring and add a connector or wire it with no connector.

The cheapest option would probably be to get a used known good compressor, complete. Look up Silas Headrick on facebook. He has several C6 parts cars right now and has always been fair with pricing. It would be pretty easy to swap the whole compressor out. Plus you would save a ton over the labor of replacing that clutch assy. His phone is 913.200.0324


Good luck

 

WTF? Clutch removal is about 10% the work of getting the compressor out and you do not have to deal with refrigerant. The wires only attach to the clutch, not to the compressor. I would try gluing the connector in position with RTV first. How do you figure compressor replacement is going to save money? At least 3 times the cost of only the AC compressor clutch replacement. If compressor is ready to fail than maybe it would save money to replace it now.

 

Could have knocked the belt off.

 

Holy old thread batman. Who even knows if this person still has the issue.

Let me start as if you had posted this back when this thread was active:

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This isn't the sloppy mechanics page.

FYI used compressors sell for around $50 and they don't have the connector glued on. Hell, a new compressor is only $250 or so.

Why replace it all and why does this save him money?

The clutch usually corrodes between the compressor body snout and clutch base causing a loose fit on reinstall(These are installed with snap rings.. Not the old school spanner nuts.). This happens on even the most well kept cars. It comes from the dissimilar metals touching. See galvanic corrosion. Sadly the aluminum is the first to go. Most dealers will quote a clutch and later call you for full replacement (prevents idiots claiming they got screwed from the beginning because someone's cousin brother told them so. e.g. your post here..). Some hacks just proceed with install at home. IMHO it is a waste of resources to fight the thing off and then end up yanking the unit anyhow. If this is done at a shop the costs just doubled nine out of ten times.

To each their own. Do it right or do it twice.