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Low-pressure Switch controls what?

nhawlman on Wed August 19, 2009 6:06 AM User is offline

Year: 2000
Make: Buick
Model: LeSabre
Engine Size: 3.8
Refrigerant Type: not Freon
Ambient Temp: 80F.
Country of Origin: United States

My 2000 LeSabre has 150,000 miles with the original Spark Plugs and Battery

the AC has been wacky since new. So has the Heater; I suspected a common sensor.
The dealer could not fix it and suspected I'm wacky. I would not go back there.
Now the AC has quit completely.

I got a can of Refrigerant/Oil/Sealer with attached hose/connector.
Directions said the Compressor must suck the contents in.
Compressor only runs if I apply air pressure to the Sensor.

I want to bypass the Sensor to fill the system.
How do I connect the THREE Sensor contacts to engage the Clutch and whatever else?

Thanksa buncha

nhawlman

NickD on Wed August 19, 2009 6:54 AM User is offline

Is that one of those X-Mart Interdynamic kits with a plastic trigger, a small very inaccurate gauge built in, and two cans of R-134a with sealer in it. My brother-in-law purchased one of those kits, was way too complicated for him, so he gave it to me. What a piece of crap, I played with it, can valve stuck, I pulled hard on that plastic trigger and broke it off, now that thing is where it belongs, in the trash can. Then I wouldn't add any of that sealer in any system, they don't say what it is, whether it's compatible with your refrigerant oil, certainly enough of it in the can that can flood the system with goo, and if it didn't do any harm, would certainly degrade your AC performance.

Are you even in the position to determine if you have a very minor leak that may just require a top off? A minor leak would be like one ounce per year, and in a ten year old vehicle, adds up to ten ounces, that would definitely hurt performance. 2.5 ounces per year would completely drain your system and you would be charging into air, if the compressor did kick on, would more than likely blow a hole in something. Really don't know where you are at or if you lost any very important lubricant that would completely destroy your system if you were able to charge it.

Would you like a heart surgeon to operate on you, using a pocket knife and a meat cleaver on you? That's about where you are at with this kit playing with your AC system.

nhawlman on Wed August 19, 2009 7:00 AM User is offline

thanks for the reply

My kit is similar, but not the same.
I would not spend the money on this old car for a pro tech.
If it explodes, it explodes.

nhawlman

Chick on Wed August 19, 2009 7:22 AM User is offlineView users profile

You cannot jump a three wire switch, it's a pressure transducer and you could fry the computer.. Only priper way to rechange the system is to pull a deep vacuum and recharge into the vacuum, it will start on it's own, stay away from leak sealers or no one will work on your car if they know it's in there, use just virgin R134a..

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

nhawlman on Wed August 19, 2009 7:44 AM User is offline

all I want to know is
what do the three contacts in the low pressure switch go to

GM Tech on Wed August 19, 2009 8:27 AM User is offline

The three wires are in the high side system transducer- IT IS NOT A SWITCH- the transducer tells the ECM whatthe system pressure is to turn on or off the compressor do to low refrigerant pressure, or high refrigerant pressure, or to turn on cooling fans at low speed or at high speed.

The three wires are signal feedback, signal reference, and common- all coming from the ECM-

You enable thius system by pressurizing it- once pressure hits the 47 psi level- compressor will turn on-- it is a V-5 (variable stroke compressor system) it does not cycle by design.- It averts freeze-up by destroking its displacement.....

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

nhawlman on Wed August 19, 2009 8:35 AM User is offline

Thanks.
If you were a Farmer.
we'd say, "You know your shit!"

Nevin

mk378 on Wed August 19, 2009 8:37 AM User is offline

Never ever put sealer into a system. Return that stuff and get some plain R-134a.

You should not have to jump anything to charge a system. Starting from vacuum, charge as much as you can liquid with the engine off. Then start the car and the compressor should engage to pull in the rest of the charge as gas through the low side. "Top up" charges should only be attempted because the charge is low that it won't cool properly, but the compressor still runs.

If the pressure is so low that the compressor won't engage at all now, there is a rather major leak and it would be futile to just recharge it. It will leak out again in a matter of days or weeks at best. Commonly the V5 will develop leaks at the case joints.

knightgang on Wed August 19, 2009 9:28 AM User is offline

Just changed a V-5 on a 97 Old Cutlass. Bad belly leak. Never would have noticed it (or known to look there) had it not been for the leak dye added to the system. Changed compressor, accumulator and OT, vacced and recharged. Blows cold now, no leaks.

GM Tech on Wed August 19, 2009 12:49 PM User is offline

I am a Farmer!!!!!

The Ranch

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Chick on Wed August 19, 2009 1:06 PM User is offlineView users profile

And, you know your S***....

-------------------------
Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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