2004 Chevy Silverado air conditioning not right

Tiny
GDBELL1
  • MEMBER
  • 2004 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 64,000 MILES
I had a new compressors and dryer and orfice tube installed also system was flushed and cleaned its seems to be blowing better but still doesn't seem right. While I am driving around 2000 rpms or higher it blows cold but while I am idling it gets warmer I am only showing 60 degrees at beat and it reads perfect on gauges. I am lost cause friends truck is the same year and model and his blows cold air around 45 to 50 degrees. Does anyone know anything about the dual air controls system on 2004 chevys?
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Tuesday, July 28th, 2009 AT 10:00 PM

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Tiny
RASMATAZ
  • MEMBER
While I am driving around 2000 rpms or higher it blows cold but while I am idling it gets warmer

An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.

Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

Some possible causes of intermittent cooling (or no cooling) on automatic A/C systems include all of the above, plus:

A problem in the control module or control head (this usually requires using a dealer scan tool to read fault codes and perform self-diagnostics).

A bad temperature sensor (an ambient air temperature sensor, interior air temperature sensor, evaporator temperature sensor, or sunload sensor). Again, a factory scan tool is usually required to perform diagnostics on the system.
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Tuesday, July 28th, 2009 AT 10:27 PM
Tiny
GDBELL1
  • MEMBER
Thanks for that but I have done all of that it seems to be when I stop and its Idling when the temp starts to drop and its not getting as cold as it should I know it should get colder than 60 degrees my other chevy gets around 45 degrees
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Tuesday, July 28th, 2009 AT 10:35 PM

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