No 134a freon pressure on rear unit

[flasher2491]

I am still having issues with my 04 explorer 4.0 2 wheel drive ac unit in rear. I wanted to see if the rear was getting freon and I unscrewed the line barely at the rear expansion valve and then opened some more and no pressure at all and maybe the reason we do not get ac in rear, I changed out the actuators, both and even replaced main ac line to compressor which needed it anyways, it was spliced by previous owner.
So what causes the line in rear unit to be empty or no freon pressure

 

[ndtscott]

I'm not sure of your cause for no line pressure but we just bought an 05 e.b. and the rear air ins't cold in ours either. I've removed the temp blend door actuator and manually moved the temp blend door and it changes to hot and normal temp but not refrigerated cold air. I haven't gotten any further than that but am very interested in the responses to your thread. I have no idea whether it is charged for the rear system or not. I didn't even realize they were seperately charged systems. I am thinking theres an orifice tube on the intake line (top one) going into the rear plenum chamber. How bout if either of us makes any progress, we let the other one know about it?

 

[EasyRhino]

Whether you have front and rear or front only HVAC units, you only have one compressor and condenser, so I'm wondering how you could have no refrigerant in the rear unit and still have working front AC????

If there is a valving system that isolates the front and rear system, that could explain why one system works and one doesn't, and might be your cause (stuck shut).

Just guessing here. My rear HVAC is still chugging along fine so far.

 

[flasher2491]

Where is the valving system located, is it the front expansion valve I looked at pictures of it and has 2 openings assuming it is for front and rear

 

[jrford]

i could be wrong but i thought it was just a 'Y' fitting, no valves. I would guess your not getting much cool air up front. When mine ran low on freon, the front didn't get as cold as it used to, rear actually did feel cool at all.

I'd take it in and have someone hook it up to 'the machine' and top it off.

 

[ndtscott]

Ive checked my freon level and its within the tolerance for optimal cooling efficiency so for mine, it's not due to a loss of refrigerant. If anyone knows where I can find a schematic for the rear ac system I'd appreciate it greatly. I'm thinking there's a rear orifice tube at the inlet into the rear plenum chanber. If there is and it's clogged, then there's not enough refrigerant passing through.