1987 Weekender - AC Troubleshooting

[h00drat]

I've done my fare share of research on the topic and found some threads like this one: http://www.thesamba.com/vw/forum/viewtopic.php?t=321941, and also read through the Bentley on the topic, but I'm still not sure where to start.

I have the overhead AC unit in a 1987 Weekender van.

The bottom line is this - when I turn on the AC on high, it blows a lot of hot air. Through my research I see that there are 2 main fuses, which I have checked, and then a whole bunch of relay's located all over the van. With the relay's, I'm not really sure what I would even be looking for if one of them were bad.

Question is this...

Should I even be trying to trouble shoot this, or should I just take it somewhere?

If I should keep trying, what am I looking for, and where should I start?
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<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
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[Zeitgeist 13]

Does your compressor clutch engage when you turn the snowflake knob clockwise? If not, then you'll need to figure out if there's an electrical issue or (most likely) the system doesn't have enough pressure to trigger the clutch to engage. Once you determine system pressure (you need a set of gauges), then you can move on to the blower issues. Without the compressor pumping, you'll get no love from the AC.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[h00drat]

[Zeitgeist 13]

It's not a dumb question, but it is pretty basic. You can have an assistant turn the key to the on position and then turn the snowflake clockwise. You should hear and see the clutch engage. If not, then you can jump 12v from the alternator directly to the red/black (can't remember which color) connection to see if the clutch even works. If it does, then remove the black cover on the suction port just behind the compressor and depress the Schrader valve. It should have some kind of residual pressure in there. If not, then the adventure begins...
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[h00drat]

So with the key in the "on" position definitely nothing happening back there when I turn the AC on. Checked the schrader valve and there's no pressure there either.

Worth trying to jump it from the alternator as you mentioned, or just assume it's toast?
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[Zeitgeist 13]

Well, it would be nice to know whether the clutch is good, but the lack of residual pressure means you have other more "pressing" issues to attend to if you want to ressurrect AC. You can remove the belt and see if the compressor will rotate freely by hand, but again...you'll probably need to open up the system and start replacing parts--drier, expansion valve, seals, pressure/temp switches, oil, etc.

It's well worth the effort and expense
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[h00drat]

[Terry Kay]

CLICK-
RRRRRRR.

Take the van to an AC guy.
_________________
T.K.

[h00drat]

[Zeitgeist 13]

The AC pulley defaults to just freewheeling around the compressor shaft until the clutch locks it and the shaft together. The clutch is the disc-looking thing that sits at the end of the pulley assembly. With the engine running, you'll see that it's sitting stationary while the pulley spins behind it. If you were to trigger the clutch, it would then begin spinning along with the pulley. It makes a rather distinct and fairly loud click! when it's energized. With no residual system pressure it's not going to click! unless you jump it with 12v directly.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[h00drat]

Okay, so the AC switch is definitely not engaging the clutch. However per your recommendation I jumped it from the alt and it did engage. So I should be trying to track down an issue related to the switch??
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[Terry Kay]

You should be looking for the receipt to find out the last time it was serviced, and what kinda refrigerant is in it first.

Then get a manifold & gauges on the low & high pressure sides and find out how much there is in it.

If there isn't anything--time to clean out the system, evac, and load her up.

Start there.
_________________
T.K.

[djkeev]

[h00drat]

Cool, thanks guys. Not what I was hoping to hear, but it is what it is.
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[h00drat]

[Terry Kay]

Dave said it, I say it.

There is a low pressure switch in the lines.
Got low freon, you'll have low pressure, and the switch will prevent the compresor from kicking on and eating itself alive.

Prior to making crazy calls telling folks what they should do, take a month or two off, and do some intense AC studies.
Figure out what does what, when & where .

I'm not bum rapping you, I just don't want folks who also don't know getting in trouble, costing them more money from incorrect information being passed on.

Get an AC instruction/training manual, put it in thr john, and do some reading in your free time.
Get some gauges to verify what is in the system first.
It is electrical.
The switch is preventing the compressor from operating due to low freon pressure, or no freon pressure.
_________________
T.K.

[h00drat]

[Terry Kay]

Well, your kinda asking questions open ended .

If the compressor doesn't fire up, don't force the issue on your own, with zero AC tools.

Go buy the good book, buy the tools, and have at it.

I feel this way.
No tools, no self absorbed knowledge?
Leave it alone.
You're shooting blanks.

You cannot work on the AC without the proper equipment.
And that's pretty much a big period.
_________________
T.K.

[h00drat]

Yeah, I don't have AC tools or knowledge, so at this point I'll take it to a pro.

I do however have electrical knowledge. The only reason I was working on this myself was to see if the issue WAS an electrical issue which I could fix as apposed to a mechanical issue which I could not.

You guys helped me diagnose it, so that's cool.
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[djkeev]

The most common problem is low refrigerant.
Initially assume that is correct.
Until you verify the status of the refrigerant you cannot proceed.
It MAY still be electrical but rule out refrigerant first.

Dave
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