Is there any way to get at the evaporator on the AC system in a 2008 Yukon Denali to remove dust and debris without tearing the whole dash out of it?
Here's the issue. AC system was serviced, performed fine for several months. No leaks for coolant to get out, etc. Everything is fine. Compressor fined. System was cleaned and serviced top to bottom and no electrical/component/computer/etc., can be found.
AC is well sub par suddenly. If you turn up the fan to deliver cool air more than one or two notches the air temp goes from about 50-60 degrees F up to about 5 degrees below ambient outside air temps. Turn the fan down to the lowest setting and the air will get down to 40 degrees F. Turn it up any and the air out put goes up to 65-70 F. "Auto" feature is useless and simply does not cool at all.
Now here's the kicker: in order to get anything resembling feeble cool air you have to turn the fan down to nearly the lowest setting and thus disable the "auto" feature. Then you have to turn on the "Auxiliary" system for the rear passengers, and then, maybe, it might give you 60 to 65 degrees out of the vents.
The dealer claims that there is nothing wrong with the system and says I just have to live with the poor design and tough nuts there's nothing they can do. And they want a heap of money just to see if there is dust on the evaporator in the heater box area. It would be cheaper to just rip out the whole system, top to bottom and replace it all than just dust off the evaporator fins. And the dealer says that there is no guarantee that replacing the whole system will correct the problem and probably won't. Essentially they told me that the AC design for this year is just sub-par and there is no means to correct the issue. As a side note, the 2008 is the one year they do not have an air cabin filter in the system.
Now, the reason for me suspecting dust and debris in the fins of the evaporator is from a persistent issue with this vehicle (promise you all won't laugh at this one ). I spend a lot of time in Northeast Arkansas where there is a lot of rice patties, which are flooded, which means that there are a lot of mosquitos. And I mean a lot of mosquitos. 100-200 mosquitos per cubic foot of air at night). So, I roll up the windows, turn on the AC on recirculate and when I do, mosquitos are expelled from the AC vents like a swarm of locusts to suck the occupants of the vehicle of blood like an infestation of vampires. I feel like I'm driving a vehicle designed by Alfred Hitchcock and having George Carlin riding shotgun at the same time.
I was thinking of dropping the kick guard, dropping the blowing motor and seeing if I could dust off the debris but I suspect the design engineers did something to preclude this remedy as per "Gray's Law'"*
*Gray's Law: "Incompetence carried to a sufficiently advance level is absolutely indistinguishable from deliberate malice."