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Discussion Starter · #1 ·
I am a proud owner of a 99 GMC Yukon. Its has a little lift, nice big tires, headers and dual exhuast. I freaking love it!

I have a PROBLEM though....my ac and heater sux! The heater only works when I am going 70+ mph and only is hot for maybe a minute. The ac does the exact same thing. I have put freon in it...nothing happened. I changed out the Heater Valve...still no heat. Then under the driver dash I found that the Blend Door Actuator arm was loose so I put the little plastic deals and spring bake in the arm...again nothing. No heat no ac. It blows great though.

Im so frustrated with this i went through the winter with no heat and now summer time I need ac.

Please help me out!

Krystal J.
Texas
 

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I am a proud owner of a 99 GMC Yukon. Its has a little lift, nice big tires, headers and dual exhuast. I freaking love it!

I have a PROBLEM though....my ac and heater sux! The heater only works when I am going 70+ mph and only is Ihot for maybe a minute. The ac does the exact same thing. I have put freon in it...nothing happened. I changed out the Heater Valve...still no heat. Then under the driver dash I found that the Blend Door Actuator arm was loose so I put the little plastic deals and spring bake in the arm...again nothing. No heat no ac. It blows great though.

Im so frustrated with this i went through the winter with no heat and now summer time I need ac.

Please help me out!

Krystal J.
Texas
I no expert but you may have more than one issue....have you re placed the thermostat?

Al so is your ac compressor working..and no leaks?
 

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Discussion Starter · #3 ·
The thermostat is good. I dont think its the compressor only because it still blows air. As far as leaks im not sure. Where would I find the leak if there is one?
 

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The thermostat is good. I dont think its the compressor only because it still blows air. As far as leaks im not sure. Where would I find the leak if there is one?
The fan will blow even if the ac compressor is bad..the fan motor runs the blower but the ac compressor is what makes it cold along with the freon.

For leaks there is a kit you can buy that injects a dye to see where its leaking. The thermostat is usually near the radiator.
 

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Ok...where would I find the compressor? And do you know how I can check to see if its not working? Also..how do I check the thermostat?

Thank you for helping me out! :)
 

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Ok...where would I find the compressor? And do you know how I can check to see if its not working? Also..how do I check the thermostat?

Thank you for helping me out! :)
The compressor is usually on the left side of the motor as your looking at the motor up towards the front on the top. It is driven by your belt. When you have your AC on it will kick on and off as needed...you should be able to hear it kick on.

The thermostat is near the radiator ... I dont know if you can really tell if they are bad or not...Its been years since I had a vehicle where I needed to replace one but I had a 95 siverado where i replaced one and it was under 10 bucks for the thermostat. Its one of those things you can afford to replace it as part of your trouble shooting steps and you wont be mad if it doesnt work!
 
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