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AC questions - mine doesn't work and it's been hot for months (and I'm moving slowly)

AJMBLAZER

AJMBLAZER

Better to be lucky than good.
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The Blazer is a 6.2L diesel equipped '89 Blazer. Came factory with AC.

When kennyw picked it up for me in Seattle the previous owner told him he didn't use the AC because the pulley squealed.:confused:

I drove it back from Seattle last June and from day 1, no AC, no squeal. All seems to turn and spin just fine. The AC definitely does not work but nothing looks abnormal or broken.

What can I trouble shoot before I take it to a shop and go, "I need AC and here's a grand.":crazy:
 
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Disconnect the low pressure switch wire and jump the terminals then turn the A/C on and see if the compressor cycles, if it does it is low on freon and needs to be charged. If this is the case a shop should look for any leaks first, fix and leaks then recharge the system.
 
Yeah, I'm not a big fan of those home AC recharge kits. That stuff isn't friendly and not cheap. I'll leave the dirty work to the professionals in regards to AC.

Okay, where's the low pressure switch?

Green cap on the fill port means it's been changed to R134, correct? Neighbor said that but I'm unsure of his capabilities.

Few years ago a former coworker of mine asked me to do one of those for him, I said no, so he and his cousin did it which he then triumphantly informed me of. Less than a week later it had all leaked out and he never did fix it before he traded it in. Money down the drain.
 
4X4HIGH said:
Disconnect the low pressure switch wire and jump the terminals then turn the A/C on and see if the compressor cycles, if it does it is low on freon and needs to be charged. If this is the case a shop should look for any leaks first, fix and leaks then recharge the system.
Click to expand...
So. It's been a month, I've moved, set up the new place, and actually have some semblance of a garage again. Meanwhile it's even hotter and we haven't hit June yet.

My questions still stand. How do I check this stuff out, where's the low pressure switch, and the green cap means R134 correct?
 
That the little dohickey with like two or three prongs sticking out of the "suitcase"?
 
4X4HIGH said:
Disconnect the low pressure switch wire and jump the terminals then turn the A/C on and see if the compressor cycles, if it does it is low on freon and needs to be charged. If this is the case a shop should look for any leaks first, fix and leaks then recharge the system.
Click to expand...


It won't cycle if the switch is jumpered... that's why the switch is there to begin with.

The switch is on the accumulator "canister". Start the truck, turn on AC, jump the switch, then immediately feel the low side line coming out of the compressor (the bigger one, the accumulator is on it too). If it doesn't start to get cold, remove the jumper and shut off the truck as it likely has very little or no freon.
 
4X4HIGH said:
Disconnect the low pressure switch wire and jump the terminals then turn the A/C on and see if the compressor cycles, if it does it is low on freon and needs to be charged. If this is the case a shop should look for any leaks first, fix and leaks then recharge the system.
Click to expand...

Nevermind my first response, I think I just misunderstood what you were saying.

It's possible for the switch to be bad too though, not always a lack of freon.
 
Take your multi-meter and check continuity across the switch. If there's no continuity, the switch is bad. If the switch is good, check for 12v at the compressor wire.

The low pressure switch tells the compressor to shut off if there is little/no pressure in the system. There is no problem bypassing the switch for troubleshooting purposes. Same story with the high pressure switch. Pointless to put your hands on the low side line after bypassing the switch, it's pretty obvious when/if the compressor clutch engages. Either way, if there's no freon in the system in the first place, the line obviously isn't going to get cold.

That said, my bet is on there being no charge in the system. No charge = a leak somewhere.

I wouldn't trust the green cap thing, any color cap can be screwed onto a service port. Most of the time there's no cap at all. :haha:




Oh yeah, I am an EPA 608/609 Certified A/C Tech. I don't have any experience on these trucks, just MRAP's, HMMWV's and HEMTT's. The basic theory is the same though. ;)
 
If it has been converted it should be obvious by the size of the charging port. R-12 uses a very small port that looks like a valve stem, R-134a uses a large port that is similiar to the connectors on air compressors.

Low pressure switch is the 2 wire connector going to the large silver jug by the suitcase. Remove the wiring connector and with the engine running jumper the two terminals on the connector and see if the compressor engages.

If it does, then you need to have it checked out, find the leak, repair the leak, then vacuum and charge the system.

If it doesn't engage the clutch verify the connector to the compressor is hooked up. If that is good the compressor or clutch is bad and will need replacement. After that change it will require vacuuming and charging.
 
lectric80 said:
If it has been converted it should be obvious by the size of the charging port. R-12 uses a very small port that looks like a valve stem, R-134a uses a large port that is similiar to the connectors on air compressors.
Click to expand...
Well, looks to me like it has the bigger, air connector style port(s?).

Low pressure switch is the 2 wire connector going to the large silver jug by the suitcase. Remove the wiring connector and with the engine running jumper the two terminals on the connector and see if the compressor engages.
Click to expand...
Ah, I got it now, it's the OTHER plug in the picture where I'm pointing at the wrong plug. Gotcha.
If it does, then you need to have it checked out, find the leak, repair the leak, then vacuum and charge the system.

If it doesn't engage the clutch verify the connector to the compressor is hooked up. If that is good the compressor or clutch is bad and will need replacement. After that change it will require vacuuming and charging.
Click to expand...
After a week of repairing other people's cars...it's 90 something today and I was boiling after my 30 min ride home. I need to fix this.

0601102015.jpg

0601102016.jpg

0601102017.jpg

0601102018.jpg
 
In that last picture, is that a hint of bright green dye on the fitting? If so, it should be easy to find the leak with a UV light.
 
Yes, actually, it does have green stuff around it. Was going to ask about that.

Do the fittings look like the R134a fittings?
 
Yep, those look like the 134a fittings.
In fact, if you look closely at the next to last picture, the one on the line, you should see that it is a fitting made on the line with another fitting screwed down on top.

That is how they converted the fittings to 134a. They had some fittings with threads that bit into the original threads and caused them to lock to the original ones.

If that green is the leak detecting dye, its kind of a double edged sword.
On the one hand, it should be easy to spot the leak, because it glows under UV light. On the other hand, the fact its in there, probably means its had leaks before and they might have not been fixed properly.

J.
 
Considering the guy told Kennyw the compressor squealed so he just never used AC and the compressor doesn't squeal at all...just no AC...I'd bet there's something wrong. Praying...PRAYING...that it's just the thing is empty and the guy was a tightwad. Dubious though.

I was going to tough it out but now I'm almost ready to just take it to an AC place and give them a paycheck to fix it.
 
Hang in there a little longer.
Even if you decide to let someone else fix it, the more you know about what is wrong, the less likely you will get ripped off, and the better idea how much its going to cost beforehand.
The low pressure switch is the round switch on the big shiny 8 sided round thing just to the right of where you are pointing just like you thought.

Should be two connections, just short across them to see if the compressor kicks in.

BTW, unless I am mistaken, and if I am I'm sure that I will get corrected quickly, the plug you were pointing to is the fan resistor pack.
If your fan ever starts running only on high, that is where you go.

However, DO NOT turn the fan on with that tab removed from the housing.
You can take it loose if you are curious, and you will see some shiny coils of wire.

They are the resistors that get switched in to give you the different fan speeds.
High is no resistors at all. So, if the pack goes bad, high is all that will work.

BUT, they are stuck in that housing for a reason. They run HOT when working, and will burn up quickly unless they are in there so the fan can blow on them.
So only take them out with the fan off.

J.
 
Yeah, that got disconnected last summer on accident when I disconnected the heater core. Not much fan. Whoops.

I looked at the picture as I was posting earlier and went, "oh dumb ****,on the silver thing, THOSE WIRES!"
 
ill be doing this soon. my 83 had no belt, so i am debating putting a belt on and seeing if the compressor is locked up (something you may need to try as well seeing as it was "squeeling", and then if it either needs charge or compressors bad i plan to replace all seals, new accumilator and new orifice tube. then take it to a shop have them dry it and charge it for me (buddies dads shop)
 
I just fixed the A/C in my S10. It never worked since I bought it, so I ran a jumper wire to apply 12v directly to the compressor clutch. It engaged and ran but never felt any temperature difference between the compressor outlet and inlet. So I charged maybe a few ounces into the system and it started working. So I shut off the engine and listened for leaks. The compressor turned out to be leaking slightly so I replaced the compressor, pulled a vacuum on the system and it held. Then I proceded to charge it full and now I have ice cold a/c.

Things to look for:
-Does the compressor clutch spin by hand (the part inside the pulley)
-When compressor is running wait to feel a temp difference between compressor ports, it may take a min or two
-Don't forget about oil in the system
 
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