Can't run car off cliff so need help with AC

[jfields1114]

Just bought a used 2020 yukon slt with 65k miles 2 weeks ago. When dealer sold it to me the AC "wasn't cold" according to the sales rep so they did a dye test and found no leaks , added freon, and called it a day.

Something is very wrong with the AC. I have had it back to the dealer 3x since buying it two weeks ago and it just acted up again this morning. I'm desperate for ideas

The AC will blow ice cold on both sides for some period (varies) then all of the sudden the passenger side will blow blistering hot. I bought a temp gun and when this happens the temp is always north of 160 degrees. Not good in 98 degree weather and 2 little kids in the car.

The hot will stay hot for anywhere from just a few seconds to 20 or more minutes. Again, just on the passenger side.

I sent videos about blend doors failing to the service department and supposedly they replaced them on the last round but it's not clear to me how many they replaced and whether they only did the doors or the actuators (under the impression these are 2 different parts)

Any ideas ?

 

[jfields1114]

Should also add im just a mom who knows nothing about cars

 

[wjburken]

Sounds like you have a blend door actuator that is still acting up or was a dud. These actuators direct the flow either over the A/C coils or the heater core. If the driver side is blowing cold while you’re getting hot air in the passenger side, this is where I would start looking. If they replaced somw of them, I’d double check the harness connection. Also, not sure about your generation of vehicle, but there may be a re-learn/calibration process that needs to be followed.

 

[Doubeleive]

Should also add im just a mom who knows nothing about cars

you are somewhat limited to what you can do as far repairing it yourself without a scanner that can read any error codes, these type of codes are not shown as a "check engine light" or anything like that, the BCM (vehicle computer) should self-check the hvac function and keep a record when a error such as a blend-door malfunction occurs, these types of codes are usually "B" codes (body codes) and it will record how many times it has occured or it will just show a general error for the specific location and is noted as a "feedback" error, where the BCM knows the blend door is not operating properly. the error code tells the technician which one it is that is failing. Sometimes these are just "temporary" errors where it may not pass one time, but did the 2nd time. (this will be there argument as far as repairs) but if one of those errors is for the passenger side then be a squeaky wheel and insist they take a deeper look at it.
so.... if this is a GM dealer the technician should be able to see that data, if it is a used car or other brand dealer, they "should" have the tools to check this as well.
It may be helpfull if you educate yourself on this enough to make it clear to the dealer that they should check for these errors and not just throw parts at it or send you on your way like your dumb and dont know anything with them hoping you do not return and then they don't have to spend more money on repairs.
the scanner can be used to "reset" these errors and then it can be checked again later to see if the same error returns.

 

[gtrslngrchris]

If this generation works like my GMT800s then you can catch the passenger side actuator when it is full cold and just unplug it and you will have forced cold on that side. My 2003 has been acting up regardless of how many times I replace the blend door or the a/c control panel and I eventually just popped off the vent reached in and unplugged it while cold and I'll continue to be pleased with the solution until winter rolls around.

 

[jfields1114]

you are somewhat limited to what you can do as far repairing it yourself without a scanner that can read any error codes, these type of codes are not shown as a "check engine light" or anything like that, the BCM (vehicle computer) should self-check the hvac function and keep a record when a error such as a blend-door malfunction occurs, these types of codes are usually "B" codes (body codes) and it will record how many times it has occured or it will just show a general error for the specific location and is noted as a "feedback" error, where the BCM knows the blend door is not operating properly. the error code tells the technician which one it is that is failing. Sometimes these are just "temporary" errors where it may not pass one time, but did the 2nd time. (this will be there argument as far as repairs) but if one of those errors is for the passenger side then be a squeaky wheel and insist they take a deeper look at it.
so.... if this is a GM dealer the technician should be able to see that data, if it is a used car or other brand dealer, they "should" have the tools to check this as well.
It may be helpfull if you educate yourself on this enough to make it clear to the dealer that they should check for these errors and not just throw parts at it or send you on your way like your dumb and dont know anything with them hoping you do not return and then they don't have to spend more money on repairs.
the scanner can be used to "reset" these errors and then it can be checked again later to see if the same error returns.

Thank you for all of this!

 

[jfields1114]

Sounds like you have a blend door actuator that is still acting up or was a dud. These actuators direct the flow either over the A/C coils or the heater core. If the driver side is blowing cold while you’re getting hot air in the passenger side, this is where I would start looking. If they replaced somw of them, I’d double check the harness connection. Also, not sure about your generation of vehicle, but there may be a re-learn/calibration process that needs to be followed.

Thank you, very helpful!