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Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 1808
Experience:  ASE Master Certification. GM World Class Certification
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2000 Buick Le saber a/c not working properly. compressor

Customer Question

2000 Buick Le saber a/c not working properly. compressor engages but the cooling fan will not come on to cool the condenser. I unplug the coolant temp sensor and they came on, what is my next step.
Submitted: 4 months ago.
Category: Buick
Expert:  Reggie Whiddon replied 4 months ago.

Hi im Reggie thanks for using JustAnswer. Put my years of experience and training to work for you

Expert:  Reggie Whiddon replied 4 months ago.

Do you haVe a set of manifold gauges so we can check the operating pressures of the system both high and low side

Expert:  Reggie Whiddon replied 4 months ago.

That is our next step. We need to confirm that the pressure is there to close the switch for fan operation.

Customer: replied 4 months ago.
Ac line is cold and compressor is engaged
Expert:  Reggie Whiddon replied 4 months ago.

so you dont have any gauges. Okay well lets assume the pressure is there and the fan is being requested. Let me pull up the wiring

Expert:  Reggie Whiddon replied 4 months ago.

the high pressure sensor is in the line behind the ac compressor check and make sure it is plugged up

Expert:  Reggie Whiddon replied 4 months ago.

That sensor is what the ecm uses as an input to turn the cooling fans on for the ac system. Once head pressure climbs in the high side it turns fans on perhaps it got pulled loose or left off from a previous repair

Customer: replied 4 months ago.
150 high 28low side
Customer: replied 4 months ago.
high pressure sensor is plugged up
Expert:  Reggie Whiddon replied 4 months ago.

That switch doesnt close until 225 psi I beleive if you are not getting above 150 it want cut on.

Expert:  Reggie Whiddon replied 4 months ago.

You said you could disconnect the temp sensor and fans activate so we know the fans and relays are good. What happens if you disconnect the high pressure sensor and put a jumper in terminals fans should come on then if they do then either the sensor is bad or your not building enough head pressure to require fans. Does your ac cool if your going down the road?

Customer: replied 4 months ago.
with coolant temp sensor disconnected fans activates, The high pressure switch has 3 wires which ones to jumper
Expert:  Reggie Whiddon replied 4 months ago.

LEtr me look up right quick

Expert:  Reggie Whiddon replied 4 months ago.

jump the gray to the red and black

Expert:  Reggie Whiddon replied 4 months ago.

those pressure readings you gave me is that as high as the high side gets

and does your ac cool if driving on road

Customer: replied 4 months ago.
This is what I have, when I disconnected the high pressure switch the clutch for the compressor disengages and when I try to jumper the wires fans still will not come on. Also when I plug the high pressure switch back in the clutch kicks in again.
Customer: replied 4 months ago.
Still waiting for a response
Customer: replied 4 months ago.
it's been 24hrs are you going to respond
Expert:  Reggie Whiddon replied 3 months ago.

Sir i am sorry my internet has been down can i still help you

Expert:  Reggie Whiddon replied 3 months ago.

With everything plugged up, i know the fans dont come on but if you drive the car down the road does the ac cool