sundog

So

I need some additional brain power to resolve this issue. I've had several conversations with mechanics and none of them are sure where the issue lies, and given the cost of "investigating" it, I'd like direction first.

2007 Chevy Uplander LS

AC blows ice cold out of passenger side vents. Luke warm or ambient (maybe slightly colder) out of drivers side vents
AC is CORRECT pressures
AC drops temp 20+ degrees from ambient out passenger vent
Mode select switch works fine
Temp control also works fine
HEAT will blow out of all vents.

*****Most importantly this is NOT a dual zone control setup so it is NOT a drivers actuator*****

*Point of interest, at or about the same time this issue started my wife noticed an intermittent hissing...or sucking...noise from the dash area...I assume its related but how I don't know, the actuators are electric certainly and not vacuum operated at this manufacture year?! And yes it ONLY happens when the ac is on*

I cannot wrap my mind around this issue, and neither can the mechanics i've talked too, but ofc they are more then willing to charge me up the **** to rip it apart and figure it out.

Anyone seen this issue before?

Is it possible GM put drivers and passenger actuators in the vehicle but if it wasn't an ordered option simply didn't provide the controls?

oilcanhenry

No. There was a time when you could order a car without a heater, but that was 40+ years ago. Your vehicle has GM electric actuators standard OEM, but perhaps one is sensitive to cold air. If it blows hot air it cant be a blockage, so something else is amiss here. No, vacuum controls are long gone thankfully, so the sucking sound could be entirely unrelated to your A/C drivers vent issue. A good running A/C system should be putting out cold air at 38 to 42 Farenhieght at the dash vents. Does the cold air side push out more volume of cold air now?

sundog

@oilcanhenry

No the airflow is pretty even across the vents, in fact in any mode. And it was my understanding the AC should drop the ambient temperature apprx 20 degrees, which is in fact about what its doing. My last measurement outside ambient was 86-88 AC was pushing 62-64 out the vent. Now that was from a hot car that had not been running, just from a dead start to measuring temps.

I cannot wrap my head around this issue. It just makes no sense. As I understand it this car with no dual zone control should have 3 actuators. They would be a Mode actuator, a Blend actuator and one that opens and closes off inside air....none of those would have this affect if it were malfunctioning...at least I don't believe they would....?

oilcanhenry

I specialized in repairing automotive A/C repair, many years ago, so I can assure you that be it R-12 or R134A refrigerant, I can always drop the vent outlet to 42 F minimum, even on an old 1988 C-2500 Cheyenne, converted to work with R134A, as long a the system is working properly.

Yes, your air blend actuator(s) could well be the issue here. It's been noted in other late model Chevy's lately.

Perhaps your evaporator is deflecting the cold air for some unknown reason, as yet undiscovered, but I would go with a air actuator defect taking an educated guess.

Are you having any other issues like water in the climate control box or any condensation? Does the interior air-recycle control work properly? It's possible that the heater is not completely shutting down, and is shunting over to the driver's side, but that too is a only a simple guess.

sundog

I'll take your word for it on the temp drop, I'll fiddle with that later on.

As to the rest No, no other issues air recycle works etc etc....

Question, if it was the blend actuator why would i get cold air out of the passenger side and not the driver side? Wouldn't it affect both passenger and driver equally if that were the case?
Either way I'm going to pull it apart myself later this week or weekend I guess, I should be able to see the actuators working once I get them exposed.