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a/c clutch

parkav

Full Member
134
3
18
Austria
Buick Ownership
Buick Park Avenue `95
i have a new a/c compressor in my 95 park avenue. the a/c is filled up with
R134a39.00PAG 1508.00
but now the new compressor dont works, the clutch is not active if i switch on the a/c.
there is a dkgreen and a black cable on the connector on the side of the clutch, if i turn the a/c on there must be electricitiy, correct?
but it isnt. what could be wrong?
the fuses 5a and 5d are ok.
 

HotZ28

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1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
How were you able to completely charge the system if the compressor clutch was not engaged? What is the residual pressure in the system? The clutch relay will not engage if the pressure is below specs.
 

5.0MX5

New member
19
4
3
Buick Ownership
1998 Park Avenue, 2001 Park avenue
AC work with today's coolant (R134) requires professional tools (vacuum pump and gauges at a minimum) and a professional's knowledge. There's actually a danger factor as well as performance one if the necessary tools and skills aren't available.

HotZ28 is spot on, you can't charge the system if the clutch isn't working allowing pressures to develop as the necessary coolest is added, bringing pressure and temps to spec.

If I were to read between the lines, a vacuum pump wasn't used. If that's the case, you need to head to a shop that can evacuate the system and fill from scratch.

If you haven't read this it may help.

Good Luck,
RonR
 

parkav

Full Member
134
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Austria
Buick Ownership
Buick Park Avenue `95
How many pressure is necessary for the a/c System?
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Drakito

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Southern Utah
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2003 Park Avenue Ultra
Black should be ground(negative). The green is +12vdc.
Several fuses all control the operation of the A/C Clutch. There is the interior climate control fuse, main fan, A/C relay fuse, and the main A/C high current feed. The climate control is what sends the signals to the a/c relay to turn on the clutch. So if the main control is not working, it won't send a signal to fire off the relay. The main control can sometimes check the blower motor fuse as well to make sure it works before sending the on signal. The on signal is usually a low current +12v signal in GM that turns the relay on. Usually the A/C relay and A/C high current feed are in the underhood fusebox, while the climate control and low current on signal are in the interior fusebox.
The high current feed is usually a large MAXI, ANL, JCASE or MCASE high current fuse instead of a normal ATC or MiniATC fuse.

That being said, if your pressures are too high or too low the controller will not allow the system to operate. When you put the new compressor in you need to vacuum the system empty and leave it under vacuum for around an hour to 2 hours. This makes sure nothing is in the line and the system can hold pressure. Once it has been stabilized you then use the vacuum block and A/C pressure balancer to fill the system up with oil and coolant. It usually takes me longer to vacuum, pressure test, and refill a system than it does to swap the parts out. Last one I did was 3 hours to put the new parts in(lines, compressor, drier, and condenser) and the rest of the day to vacuum, pressure test every joint, and then refill. You need specialized tools to do it correctly. I start the vacuum process and check on it after about 15 minutes, then every 30 minutes until it stabilizes at ~25-30-hg. I shut off the vacuum after it hits absolute and then spray a soapy compound on every joint to check for suction or bubbling. I then leave it for an hour and see if the vacuum has dropped. If it has I find what is leaking, repair it, and start over. It should be able to sit at 30-hg all day. Then I start the fill process, which takes me a bit as I use the 12-24oz charge cans and have to wait as they are sucked in since I use small shop mechanic tools, not the monster digital control evacuate and replenish systems.
 

parkav

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134
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18
Austria
Buick Ownership
Buick Park Avenue `95
After i renew the compressor, my car was in a professional Workshop. They set the completly a/c System under vacuum, it was solid. After that, they fill it with 39oz r134a and 8 oz PAG 150, because i have found that amount at techcoiseparts.com. are this quantitatives disclosure wrong?
 

HotZ28

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1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
Once again, was the compressor clutch engaged during the charging process?? Did it fail to engage after the service?? A lot of unknowns still exist here!
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parkav

Full Member
134
3
18
Austria
Buick Ownership
Buick Park Avenue `95
the old compressor worked good but it was leaky. so i take a new one, an delphi. the guys in the workshop use an professional filling system to fill in the r134a, the PAG and an contrast-medium in the system.
 

HotZ28

Full Member
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345
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1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
the old compressor worked good but it was leaky. so i take a new one, an delphi. the guys in the workshop use an professional filling system to fill in the r134a, the PAG and an contrast-medium in the system.
Sorry, but I will have to ask that same question again? Did the NEW compressor clutch EVER engage after the replacement & during the charge process?? Som Ting Wong here!
 
Last edited:

parkav

Full Member
134
3
18
Austria
Buick Ownership
Buick Park Avenue `95
to bee or not to bee............
update: at the compressor relay are 4 cables, 2 pink (they are allways hot if the engine runs), 1 green-white (its hot if the relay is fix on), and 1 green. when i connect the green one (i think it goes directly to the compressor) with battery + the compressor runs.
is this right?
 

parkav

Full Member
134
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Austria
Buick Ownership
Buick Park Avenue `95
how works the relay?
the green/white cable is from the pcm, and its allways + like the pink one.
I have checked the a/c request cable dk/blue, its hot if i turn the a/c on.
the pcm should be also ok, because i have another one and switch it, its also the same problem.
i think it can not be a great problem, i have only changed the compressor.
how can i check the a/c refrigerant pressure fan switch?
there are 2 pressure switch, 1 near the compressor and 1 at the accumulator?
so, what can i do now?
______________________________
 

parkav

Full Member
134
3
18
Austria
Buick Ownership
Buick Park Avenue `95
i try at the green/white cable from the relay to give battery -; the relay closed. its necessary to change the polarity, for the relay to work on?
 

Drakito

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Southern Utah
Buick Ownership
2003 Park Avenue Ultra
Sorry, I have been trying to hunt down a wiring diagram for your car so I can give you the actual vehicle information. Currently been just giving you general help.
I found it here Buick Workshop Manuals > Park Avenue V6-3.8L VIN K (1995) > Heating and Air Conditioning > Accumulator HVAC > Component Information > Technical Service Bulletins > Customer Interest for Accumulator HVAC: > 731207
But you will need to go page by page through it. Its a pretty slow site, but has what you need. The full Factory service manual.
 

parkav

Full Member
134
3
18
Austria
Buick Ownership
Buick Park Avenue `95
thanks for sending this page, i restart the troubleshooting and found the mistake, the pressure Switch on the accumulator.
maybe ist to less cooling-fluid and oil in the System, maybe the Switch, i will see it if i vacuum up the System.
 

5.0MX5

New member
19
4
3
Buick Ownership
1998 Park Avenue, 2001 Park avenue
Great job trouble shooting. Good Luck!
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