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Discussion Starter #1
After searching through this and other forums I think I know the answers to the questions I'm about to ask but I wanted to double check. First some background info, My car does not have it's original engine and I'm happy to say that the computer and all that it once controlled are long gone.
My question is does the pressure switch on the power steering system simply act to provide/take away ground to the AC compressor through the computer? If I understand correctly the computer provided a ground to the AC system if the correct operating parameters where met. I'm thinking this because after doing my home work on wiring diagrams and the like then tracing the wires from the pressure switch one of them seamed to go to the no longer in the car computer. The other goes to the plug at the compressor along with the green wire from the from the pressure switch on the drier that again, if I understand correctly provides voltage to the compressor. If this is the case can I provide a ground to the compressor in place of the wire from the power steering switch so that it's control will be solely controlled by the pressure switch on the drier eliminating the power steering switch since it doesn't have a PCM to talk to any more?
The second best thing I did after getting my second Elkie was joining this site you guys have been lots of help. Thanks again, Ang.
 

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I can't answer your question, since I'm at work and nowhere near my shop manual, but trying that option seems like a worthwhile pursuit. I'd think that tapping into the pressure switch circuit might be a viable option. I'll try to thumb through the wiring diagrams when time allows.

Bill
 

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My AC went out last week and I did some troubleshooting with my shop manual. What I don't understand is why would a wire that provides power to the AC go thru the power steering? That just seems weird.
 

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Discussion Starter #4
From what I've read and think I understand when the engine is at low rpm such as it is in a parallel parking maneuver, the power steering pump builds pressure and creates a load on the engine as your turning the wheels so the switch on the steering system shuts down the AC compressor so the added load doesn't make the car stall.
 

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Its designed to turn off the compressor on very hard turns. You can also remove the switch by replacing the line with an 82-85 PS line.
 

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Discussion Starter #6
Its designed to turn off the compressor on very hard turns. You can also remove the switch by replacing the line with an 82-85 PS line.
Thats what I was thinking I was going to buy a line for a non AC car so the tee for the switch wouldn't be there.
Thanks, Ang.
 

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The ECM does not provide a ground for the compressor. The ECM does provide a ground for the idle up relay. If you want to eliminate the power steering pressure cutoff switch (yes, it turns off compressor operation during hard left or right turning,) just unplug the p/s switch and jumper or solder the two leads together.
 

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Discussion Starter #8
The ECM does not provide a ground for the compressor. The ECM does provide a ground for the idle up relay. If you want to eliminate the power steering pressure cutoff switch (yes, it turns off compressor operation during hard left or right turning,) just unplug the p/s switch and jumper or solder the two leads together.
Thanks for the reply Robert, my problem is that the only thing left from the power steering pressure switch harness is the one wire that ran to the AC compressor. Thats why I thought it was a ground given the fact that the drier/accumulator pressure switch, from what I understand supplies the positive 12v leg to the compressor. Not forgetting that the Ecm and any associated wiring is long gone back to my original question if I supply a ground to the compressor will the drier pressure switch energize the compressor when I call for AC.
Ang.
 

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Thats why I thought it was a ground given the fact that the drier/accumulator pressure switch, from what I understand supplies the positive 12v leg to the compressor.
Yes, power goes through the compressor cycling switch on the accumulator, to the power steering pressure switch and out to the compressor clutch coil.

back to my original question if I supply a ground to the compressor will the drier pressure switch energize the compressor when I call for AC.
No, the compressor clutch coil is already grounded. Run a jumper wire from the down side (dark green wire) of the accumulator pressure cycling switch to the compressor clutch coil to supply power.
 

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can hardly make left turns/u turns

From what I've read and think I understand when the engine is at low rpm such as it is in a parallel parking maneuver, the power steering pump builds pressure and creates a load on the engine as your turning the wheels so the switch on the steering system shuts down the AC compressor so the added load doesn't make the car stall.

thats odd, so are u saying everytime i make a uturn my power steering uses up more power from the engine?

I dont mean to jack the thread but i was just scanning and this is the problem i've been having with my 80 elky, i have NO LOOSE wire or anything like-wise but everytime i make a hard left my car will choke to the point where it'll shut down on U TURNS or something, odd thing is it doesnt do that on the RIGHT TURNS or RIGHT U turns
 

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Discussion Starter #11
thats odd, so are u saying everytime i make a uturn my power steering uses up more power from the engine?

I dont mean to jack the thread but i was just scanning and this is the problem i've been having with my 80 elky, i have NO LOOSE wire or anything like-wise but everytime i make a hard left my car will choke to the point where it'll shut down on U TURNS or something, odd thing is it doesnt do that on the RIGHT TURNS or RIGHT U turns
Have you ever tried to turn the wheels of your car with the engine off sitting still? Granted when it's rolling it's easier. During a u turn the engine would be at lower rpms and the steering pump puts a good load on the engine as it works to help turn the wheels, unless of coarse you just robbed a bank are being chased by the cops and the u turn is on two wheels:secret:. The switch on the power steering pump is only supposed to shut down the AC compressor if its on to help compensate for the added load on the engine.
In your case it's strange that your having that problem only with hard lefts, I don't think the power steering pump knows the difference between rights and lefts. Maybe the car is idling too low.
 

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they didnt get the pressure switch until mid 80s so the early ones dont have one.make sure your idle is at least 550 in drive with all accesories on and lights on and steering against one lock. as engines wear they have a harder time maintaining the set idle and sometimes will require a slightly higher idle to avoid stalling.the power steering pump cant tell which direction you are turning the wheel. you may want to look at your steering box for an issue.
 

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You know, I stood there and puzzled about that switch on the power steering, and I couldn't figure out what it could possibly be for. Now I know!
 

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Discussion Starter #14
Yes, power goes through the compressor cycling switch on the accumulator, to the power steering pressure switch and out to the compressor clutch coil.

Robert, again thank you dawn finally broke over Marblehead. The brain block I was having was the role of the power steering switch. I didn't realize it was the last thing the compressor heard from. I checked whats left of the wiring today, the dark green wire from the drier is still running to the compressor and I found the wire from the harness under the hvac box that ran to the power steering switch so I will run that up to the compressor to complete the loop without the power steering switch.
Ang.
 
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