Ac blows cold then hot air

SOURCE: AC Not Cooling on Passenger side

is300 has dual zone climate control
passenger side blend door actuater has probably failed

SOURCE: 2005 GMC air conditioning

hello wwwatkin,

i stated my post in the clarification post and you can not rate my solution and since rating is just as important to us as answering your questions, can you please rate me in this post?.

thank you in advance and i really would appreciate it if you rate me a fixya.

again, thank you,

drcool299

SOURCE: 2005 GMC Sierra Denali - Installed new battery; driver a/c hot

need to go to dealer to have HVAC module reprogramed. whenever diconnecting battery power on these vehicles you can connect a 9 volt battery between neg and pos to keep the memory in the computers. I am an master ase technician and 5 classes from gm world class tech.

SOURCE: Replaced the battery on a GMC Sierra 2005. Turned

you have taken the calibration out of sink. you will now have to remove battery power again for about 5 minutes. after this time reconnect the battery. then turn key to on position for 3 minutes but do not touch the heater control or temperature controls. This should allow the heater and ac system to recalibrate. once the 3 minutes is up turn key off and then back on and start truck.. Try your controls again and see what happens. if no change then dealer will have to reprogram the heater control calibration for you.

SOURCE: 2008 legacy air conditioner was blowing cool air but not cold I added one can 134a on low pressure side with motor running ac on high cold now it only blows hot air

I highly recommend that you get it checked by a professional. You may have a restriction in your system, or the system is way overcharged. In either of these cases, the possibility of high pressure causing lines or hoses to burst and possible severe damage to your vehicle, like a destroyed compressor, is very likely.

Also, check the can that you added freon from. Many of the small cans of freon sold at the local parts retailers have several ounces of "oil charge" in them. Many times, when these cans are used to fill the system, the system ends up saturated with too much oil, which can also cause dangerously high head pressures, which can result in severe damage to your vehicle. In these cases, the system must be evacuated and flushed out to reduce the amount of oil in the system before it will cool properly.