So, the hundred dollar question today is: I have a 01 xj, and the hvac unit does nothing but stay on defrost. The a/c will not kick in even. I put a new switch in the dash, it did,'t help, there are no vacuum leaks in that system. My thought is replace the blend door actuator, but does the actuator have the switch to turn on the ac? I need to figure this out soon, as it is supposed to hit 80 today,(It will be 50 again tomorrow, so I guess it don' t matter) Also, my power windows don't work and I will be pulling the door apart to find the broken wire. So I have enough time and diversions before I get to the ac problem

 

it might be the head unit, if you're sure there is no vacuum leak.

but the a/c pump engages on defrost. you should hear it kick in and out. does this by factory default.

i think you have a leak somwhere. but you can pull the head unit and replace it with one from a junk yard jeep. they're easy to remove.

 

Cowboy

You have two issues here. Staying on defrost is a sign of no vacuum to the controls. They default to defrost. The second is that you probably are low on refrigerant. If this happens, there is a low pressure switch that will keep the compressor from coming on and ruining itself.

Get your vacuum going and charge it up and it will work.

 

^^^^ yeah when you are low on r13 it will give you some issues like you are describing. i had low pressure in mine last year and it was doing exactly what you are saying

 

here is the thing, I already tried to add r134a, and it will not accept it. The compressor never kicks in! As for the vacuum, where do the vaccum come from for the hvac unit, I am sure I will find it eventually, does anyone have any diagrams out there?

 

The vacuum comes through the firewall via a little hard plastic line. There is one next to it that goes to a valve in the heater hose.

Are you putting the fitting on the liquid side or vapor side? Also, 134A is a blend, make sure the can is upside down when adding. Your fitting should go on the line that goes to the compressor so once it starts running it will suck the can dry.

 

on the no window situation....if they all work from the D/S master controll panel then your window lock out switch is bad.(can be bypassed) If they just plain dont work...im 95% sure your master switch panel is going out....VERY common issue. no need to tear all the doors apart.

 

Let me be the 5% spoiler then. I have about 10 wires broken in the flex tube between the door and a pillar. In the process of soldering them right now, neede a beer break. Thanks for the advice though