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Compressor won't engage

TH on Thu May 23, 2013 10:19 AM User is offline

Year: 2004
Make: Chevrolet
Model: Aveo
Engine Size: 1.6
Refrigerant Type: R134a
Ambient Temp: 70
Pressure Low: 85
Pressure High: 85
Country of Origin: United States


Hello all,
I've checked the fuses and relays. Cooling fans turn on. Pressures high and low are 85 on both.
What should I check from here.
Any suggestions? Thanks in advance.
Tom






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T. Hauser

WyrTwister on Thu May 23, 2013 12:19 PM User is offlineView users profile

Quote
Originally posted by: TH
Hello all,

I've checked the fuses and relays. Cooling fans turn on. Pressures high and low are 85 on both.

What should I check from here.

Any suggestions? Thanks in advance.

Tom



Most / all newer systems have a pressure switch that keeps the compressor clutch from activating when freon level / pressure drops below a certain value .

Having said that , my GUESS is that it is low on freon . Meaning you have a leak ( if it worked in the past ? ) . So you will most likely have to diagnose & fix the leak , vacuum the system down to a hard / deep vacuum & then charge the system with the appropriate quantity of freon .

First thing to look far is an oily deposit ( refrigerant oil leaking from the system ) any where on the components of the A/C system ? Or any other obvious damage ?

(Your " fan " belt is OK , isn't it ? )

God bless
Wyr

mk378 on Thu May 23, 2013 1:40 PM User is offline

Compressor should turn on with 85 psi static pressure at 70 F. That is a normal reading. If the fans come on that usually means the controls are OK with turning the compressor on. See if the clutch coil is getting power when it should be on. If it is, either the clutch gap is too wide or the coil is open.

WyrTwister on Thu May 23, 2013 5:17 PM User is offlineView users profile

On my 91 & 96 Chevy , the computer commanded the compressor clutch relay to turn on . Do not know if his car is simular , but I suspect it is ?

I looked up the wiring diagram on the 96 and checked at the relay . It was OK .

With the car off , I jumpered around the relay and sure enough , click , the clutch pulled in properly .
]
Vacuumed the system down , Held vacuum for about an hour & then added oil / dye , then freon . When the second can of freon , started to enter the system the pressure switch started to bring the clutch on & the compressor started cycling .

Then I started looking for leaks .

God bless
Wyr

TH on Sat May 25, 2013 9:40 AM User is offline



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T. Hauser

TH on Sat May 25, 2013 9:42 AM User is offline

Thanks for the reply, I'll check those out and let you know how I make out.
Tom

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T. Hauser

TH on Fri June 07, 2013 8:06 AM User is offline

Well I finally got to it yesterday. Found that the wire from the relay to the compressor had broke. Spliced and soldered and now she works like a charm. Thanks mk378.
Tom

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T. Hauser

WyrTwister on Sat June 08, 2013 5:49 AM User is offlineView users profile

There is never any way to tell , before you start trouble shooting , if it will be a simple ( not always simple to find ) problem or a very serious / complicated / involved problem .

Always makes be happy when I can successfully fix a problem . And being cheap , it puts an extra wide grin on my face when the fix is simple / easy / quick / cheap . :-)

God bless
Wyr

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