Ive been working on a 2001 Suburban (Yukon XL), and the rear A/C does not blow cold. The blower and heat operations are functional but cold side isn't. The front A/C blows ice cold. Is it possible someone blocked off the lines going to the rear evaporator? I do not see anywhere where the lines have been blocked off. Not that important to fix, its just one of those things that has been eating at me.

Thanks,
Cole L.

 

A shop can pull out the R134a and weigh it to determine if it's the correct amount, only real way to tell. The front uses an orifice tube and the rear uses an expansion valve. If the connections to the rear AC have been capped, should see that in the engine compartment. I'd let a pro take a look (independent ASE shop, not dealer).

 

Thanks. I will see if I can get her into the shop. Not that big of a priority since the front is cold. Could it be a possible blend door issue?

-Cole.

 

Yes, good suggestion: that could be a possibility, that an actuator in the rear is malfunctioning and a flap/door is allowing heat to mix in (I've had that happen in the front/driver side on my 2005 Yukon, and on my 1994 Suburban). Or maybe your model or year cuts off hot coolant flow to the rear when the heater is switched off or the AC is on. So unless you have access to a detailed factory service manual, this could be tough for a non-professional.

The professionals at http://autoacforum.com/ say that 60% of AC issues are due to loss of refrigerant. But a shop that knows AC - not a Brake Shop or Speedy Lube with a sign - should be able to figure out. Sometimes, all of us have to rely on a real ASE shop. You do not need a dealer for this.

 

On my 01 has computer climate control, the control where you set the temp that you want, like 72*. The rear blows hot unless you set the rear temp control all the way to the left so it is on the blue mark. While troubleshooting it I found that the blend door always closed to heat in any other positron on the control setting. I believe the problem for mine is the rear seat control box but I have not been able to find a replacement.. Anyway my point here is if you have the same type of controls try setting the control to the blue mark and see if it blows cold, perhaps your problem is the same as mine.