2000 Buick Lesabre AC/heater control

Tiny
75GL1000
  • MEMBER
  • 2000 BUICK LESABRE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 48,000 MILES
With air conditioner on heater is blowing hot
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Friday, July 31st, 2009 AT 9:35 PM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Your A/C system may have lost its charge of refrigerant, or the compressor may not be engaging when you turn on the A/C, or the blend air door inside the HVAC unit may be stuck in the HEAT position so no air goes through the A/C evaporator.

Start with the compressor. Does it engage when you turn on the A/C?

If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).

If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.

If the compressor does not engage when you jump it, the problem is a bad compressor clutch.

If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is loced up and you need a new compressor.

If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged. If you Have an A/C gauge set, hook it up and see if the system has any pressure.

If it is out of refrigerant or is low, check for leaks, then have the A/C system vacuum purged to remove air. After the air is out, it can be recharged with the specified amount of refrigerant. It is important to get any air out as this will reduce cooling efficiency and may make the compressor noisy.

My advice to you if you know nothing about A/C service is to find a repair shop that specializes in A/C repairs and let them fix your cooling problem for you. Today's A/C systems with automatic climate control are very complex and reuire special tools and know-how to diagnose and repair
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Friday, July 31st, 2009 AT 9:44 PM
Tiny
75GL1000
  • MEMBER
It's not A/c related, I had the defrost on the other morning and when I turned the A/C on and lowered the temp slide it continued to blow hot air. All air flow directions function properly, just can't get the temp to come down. Could this be the controller slid itself?
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Sunday, August 2nd, 2009 AT 12:56 PM
Tiny
MOSHBIKES21
  • MEMBER
Ok I have had same problem I think only with the door temp ajustment when heater was on wife wanted it hotter so she hit temp up on pass door. With the summer around u run the ac but only the drivers side gets cold air pass gets hot and thats it. IS this the problem you are having, if so I would replace the switch have not replaced mine but I dont use ac
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Monday, August 10th, 2009 AT 1:39 AM

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