Automotive Air Conditioning Information Forum (Archives)

c6mcfall on Sun June 24, 2012 6:26 PM

Year: 1995
Make: Vhevy
Model: Impala SS
Engine Size: 350 LT1
Refrigerant Type: R134A
Country of Origin: United States

My compressor is not engaging when I turn the AC on. The entire system is about 3 years old, I checked the fuses they are good.. Thought it might be the coil? Just to see I disconnected the connector on the accumulator and short across the terminals on the connector to see if the compressor would engage and it didn't. I checked voltage when I pulled the connector off the accumulator and had 12.79v. I also checked to see if I was getting voltage at the pig tail at the compressor and I am not?? No voltage at all.. Why would I not be getting voltage to the compressor? Relay? I did get a new one just in case but it made no difference

Edited: Sun June 24, 2012 at 8:00 PM by c6mcfall

GM Tech on Mon June 25, 2012 5:12 AM

Did you unhook battery for 10 seconds to reset low refrigerant code 46?

Did you have Autozone read your codes for a code 46?

Service engine light does NOT light for a code 46 FYI

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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......

c6mcfall on Tue June 26, 2012 4:27 AM

I will check it for codes tonight, I can hook it up to my laptop, no service engine light came on.. yet.

c6mcfall on Sat August 04, 2012 11:02 AM

Ok I finally got around to checking this and I'm getting MALF error 66 A/C Pressure Sensor Open/Short, MALF 67 A/C Pressure Sensor Degradation errors

I reset and the codes go away, still no engagement of clutch. Now I get no MALF errors

I jumper connector on the accumulator and short across the terminals on the connector to see if the compressor would engage and it didn't

So?? Where to go from here...

c6mcfall on Sat August 04, 2012 12:56 PM

checked the resistance of the coil.. connected my ohm meter to the connector and getting 4.2 ohms..

c6mcfall on Sat August 04, 2012 3:54 PM

Ok, so I checked the relay, it's fine.. took off the cap, manually engaged and it worked. have 34 Low / 185 high side. Any ideas?

Leggie on Mon August 06, 2012 5:31 AM

What is the pressure in system when its allowed to sit for a while? The value in psi should be about the same value as temperature in Fahrenheit.

I don't know if that sensor is a transducer or a switch... if it's a transducer, jumping isn't the right approach.

bohica2xo on Mon August 06, 2012 11:59 AM

You can't jumper 3 wire sensors. GM likes to use sensors rather than switches. The multiple codes would indicate a bad sensor.

B.



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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.