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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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Discussion Starter #1
I think I could have a bad high pressure/pressure cycling switch on my 05 Outback. I've been looking and can't seem to find just the switch. I have found the entire low pressure line but I got to believe I can buy the switch by itself? I think I'll replace the expansion valve too while I have the system evacuated.

The compressor doesn't cycle at any hi/lo pressures on my manifold gauges. I have checked the relay and it seems to work properly.
When I'm driving with the AC on it will run to a point then the compressor kicks out but when I turn the key off and restart the engine, the compressor comes back on, but only for a little while.

I have a new compressor and condenser/dryer and new O rings and I know I don't have any leaks. When the compressor runs, it gets cold inside the cabin.

Any guidance is genuinely appreciated!
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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IIRC, there is only a "Trinary" switch on these systems (or "window switch"). Some compressors did have a thremal cut-out switch to prevent overheating...
 

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. . . When I'm driving with the AC on it will run to a point then the compressor kicks out but when I turn the key off and restart the engine, the compressor comes back on, but only for a little while..
. .
So, If I understand correctly, the AC works, but it just doesn't stay on. And when it shuts off, the only way to get it going again is to restart the engine.

That's what happens on the H6 when the rpm of the compressor is not consistent with the engine rpm. The ECM puts the AC system into "lockout".

In earlier years there were problems with the revolutions sensor in the compressor (only the H6 has this, not the 4 cylinder) and there's a good number of threads/posts here with exactly your symptoms. Not so much on the later model, but I guess still possible.

Is the replacement compressor a new one, or recycled used one? If new, then I think we can discount a bad rev sensor or the compressor clutch (which if slipping, leads to the same symptoms). The next possible cause is a slipping drive belt, or a deteriorating crankshaft pulley/harmonic balancer. (If the pulley on the H6 is the two piece type, the rubber material between the inner part and the outer ring could be deteriorating, and allowing the ring to rotate. That could slow the speed of the belt and the compressor. Put a white mark on the pulley extending from the center to the outer edge. Drive the car for a while and see if the line is intact after, or if the outer and inner parts no longer line up.)
 

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That's what happens on the H6 when the rpm of the compressor is not consistent with the engine rpm. The ECM puts the AC system into "lockout".
In earlier years there were problems with the revolutions sensor in the compressor (only the H6 has this, not the 4 cylinder) and there's a good number of threads/posts here with exactly your symptoms. Not so much on the later model, but I guess still possible.
ARGH !!!! AYFKM ????
Thank you for this INVALUABLE information. My 4 cylinder model is doing exactly this. Compressor comes on for a few seconds when I start the car then is done. I checked the line charge, no probs. BUT... I could not find any information on why MY compressor is a TWO wire compressor when every other subaru I've had has been single wire. Well... rev sensor feedback would certainly solve that mystery. I know you said this is limited to the 6 cylinder, but maybe the two wire compressor was a 2007 off year stupid idea. I did have quite a bit of belt squeaking. I thought I tightened it up enough but I will retry again. This is not the first time I've had a squeaky compressor belt. Why now?
I guaran-f***ingtee you this would have cost me $$$$ in replaced parts for it just to be a slipping belt.
Don't you think they'd give me a f***ing ECM engine light to at least give me a clue the compressor is locked out? Stupid.
Again, thank you.
J
 

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Lawn ornament XT
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ARGH !!!! AYFKM ????
Thank you for this INVALUABLE information. My 4 cylinder model is doing exactly this. Compressor comes on for a few seconds when I start the car then is done. I checked the line charge, no probs. BUT... I could not find any information on why MY compressor is a TWO wire compressor when every other subaru I've had has been single wire. Well... rev sensor feedback would certainly solve that mystery. I know you said this is limited to the 6 cylinder, but maybe the two wire compressor was a 2007 off year stupid idea. I did have quite a bit of belt squeaking. I thought I tightened it up enough but I will retry again. This is not the first time I've had a squeaky compressor belt. Why now?
I guaran-f***ingtee you this would have cost me $$$$ in replaced parts for it just to be a slipping belt.
Don't you think they'd give me a f***ing ECM engine light to at least give me a clue the compressor is locked out? Stupid.
Again, thank you.
J
I've never seen a 4-cylinder with lockout system. Please note, the lockout system was created specifically because the 6-cylinder car only has one accessory belt, the lockout is there to save alternator and power steering function in the event of a seized AC compressor.

4-cylinder cars should have separate belts for the AC so no lockout system is required.

AFAIK there is a signal flag for this that you can read from OBD, but it isn't linked to any indicator on the car itself.
 

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Fully agree with @rasterman provided @jhelm_waterw drives a North American 2007 H4 (as I do). If offshore, who knows . . .

. . . BUT... I could not find any information on why MY compressor is a TWO wire compressor when every other subaru I've had has been single wire. . . .
"TWO wire", as in two separate connectors, or two wires to a single connector? If the latter, that's what I have -- two wires to a two wire connector at the front; it's for the clutch electromagnet.
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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Discussion Starter #7
I think I could have a bad high pressure/pressure cycling switch on my 05 Outback. I've been looking and can't seem to find just the switch. I have found the entire low pressure line but I got to believe I can buy the switch by itself? I think I'll replace the expansion valve too while I have the system evacuated.

The compressor doesn't cycle at any hi/lo pressures on my manifold gauges. I have checked the relay and it seems to work properly.
When I'm driving with the AC on it will run to a point then the compressor kicks out but when I turn the key off and restart the engine, the compressor comes back on, but only for a little while.

I have a new compressor and condenser/dryer and new O rings and I know I don't have any leaks. When the compressor runs, it gets cold inside the cabin.

Any guidance is genuinely appreciated!
Here's a follow up to my original post that may help someone else:

The problems I was having with the compressor kicking out persisted until I broke the system down and went back through whatever could have gone wrong with the upgrade.

The final conclusion was that while replacing the compressor, as is the case with most compressors, there wasn't a sticker or warning that the new compressor contained test oil that needed to be drained and I just installed it and fired up the system. The result was that I pumped test oil throughout the entire AC system and fouled everything.

Once I realized what I'd done, I removed the descant bag from the dryer on the side of the condenser, disconnected all the lines, blew compressed air through all the lines and condenser, expansion valve and interior core. It was fouled completely!

After all the oil ceased flowing, I put new O-rings on the hoses and a new descant bag into the dryer. I also put about 2/3 the amount of PAG oil back in (because I knew I didn't get it all out) and pumped a vacuum on the system which I left for 12 hours so to pull any residual moisture from the system and verify I had no leaks.

Then, I replaced the refrigerant and started it back up. Now I have cold air and everything is working as it should.

It was a humiliating, hard lesson to learn but I came away with a clearer understanding of how the AC system works - so, guess it wasn't all bad?

Anyway, I hope this will help anyone else who's repairing their AC system.
 

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"TWO wire", as in two separate connectors, or two wires to a single connector? If the latter, that's what I have -- two wires to a two wire connector at the front; it's for the clutch electromagnet.
Yes, two wires in a single connector (which confused me)
Every compressor I've ever seen only needed one wire as the compressor itself is already grounded (no need for ground wire)
What also didn't make sense to me was I could not dig up any wiring diagrams for 2007 (or thereabouts) that showed the two wire connector.

Ok. yeah. I get that the 6 cyl wants feedback to prevent burning up a single belt in case of compressor seize. That makes total sense.
And yes, I do have two belt 4 cylinder, so... my model doesn't have rev feedback.

Maybe it's the trinary switch.
I left my test meters at my friends crib. I'll get there tomorrow and ohm it out.

Thanks to all for the input.
J
 

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Yes, two wires in a single connector (which confused me)
Every compressor I've ever seen only needed one wire as the compressor itself is already grounded (no need for ground wire)
What also didn't make sense to me was I could not dig up any wiring diagrams for 2007 (or thereabouts) that showed the two wire connector. . . .
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