O.K On my 94 aero I have never been able to get my rear air or heat to work the blower always worked but that was it. So today I took of the access panel and I think that door flap was stuck. I now have heat that works great on the bottom. I seen that there was a little radiator thing on the bottom for the heat. But I do not have any cold air blowing out the top vents when the air cond is on. Now I saw that radiator for the heat, but I did not see anything else except the blower. Is something missing for the air to work?? I see that there is some sort of plug in connector by the fan that is not plugged in to anything

 

The AC evaporator is usually placed ahead of the heater core, so you probably won't see it unless you remove the heater core. If you have any fan action at all, the fan is working, and it should work in heating or cooling mode. When you select the front panel control to AC, it should activate a door in the air box (with a vacuum line) to divert the air to the rear upper registers. I've seen the tiny vacuum lines get damaged by chafing or rodents, rendering them useless. So you might want to check that all these things are working.

 

The door is working fine, it's just not blowing"cold air" through the vents

 

Check your A/C solenoid valve this is an electronic valve that opens and allows refrigerant to flow into the rear evaporator when you want to use the rear A/C. If it is faulty discharging the system will be necessary to replace it.

It will be located on the liquid line to the evaporator (the small line).

 

Having been there and done that.....
Your heater core for the back is the one that is laying flat, near the floorboards. The evaporator core for the back unit is up and to the right of the heater core. If the panel is off you shouldn't have any problems recognizing it. If your fan is blowing hot air from the heater and your flap is working ok, the only other problem could be your solenoid valve. If you follow the routing of your high pressure line (the skinny one), it comes up through the floorboard, makes a 90 degree bend to the right, past the drier, a 90 degr downward and then a 90 degree to the left. In the center of the run between the last bend and the evaporator is the valve and the attached solenoid. With your AC on, and the switch for rear air set to "rear control", switch the rear AC off at the rear control. Turn the control to any fan position to turn the rear unit on. At this point you should hear a definite "click" from the solenoid when it activates the valve. If the valve is not working, check for voltage at the connector.

 

I only have two aluminum tubes running from the front of the van to the rear and up to what I assume is the heat core one of the tubes has a regulator on it. Am I supposed to have 4 lines if it has rear air and heat???????/

 

Two heat (from and to) and two AC (high and low pressure.

 

OK I have rear heat, but I do not have air in the rear. I looked at a '93 Aero at the wrecking yard and behind the access cover, I noticed another core in that one that I don't have. It had the 4 lines-- 2 heat, 2 air, and the hoses were cut off at the compressor. My question is what is the easiest way to remove the air condition lines or can I even use them since they have been cut off at the compresssor? The core looks like it comes off easy enough, but do I need to take the lines off at the core so I can get the lines form underneath the van out? Since my van isn't equipped with rear air, although I do have the fan and vents for it along with the rear heat). Can I use my compressor, or do I need a different one for rear air?

 

I thought that some Aeros didn't have rear air but heat only but wasn't sure.

Anyways while my Aero doesn't have rear air I have a pretty good idea how the system differs.

The compressor is the same however if you decide to do this after discharging your system you will notice a sticker on the blower you will need to charge more refrigerant for rear A/C it will say W/ Rear AC and W/O Rear A/C.

Most likely you will need to add more oil as well check out the sticker regarding that.

Your current accumulator should only have two hoses the one in the back is from the evaporator outlet and the other goes to the suction side of the compressor.

The rear A/C units have an accumulator with 3 ports one in the back for the front evaporator outlet the one to the left is for the rear evaporator outlet and the final one on the right goes to the suction side of the compressor. This should not be picked up from the scrap yard and should be purchased new.

As for the liquid lines I believe that you won't need to replace the condensor however you will need to remove the current liquid line and replace it with the one for rear a/c I believe that this line rather then just feeding straight from the condenser to the front evaporator inlet as it does in front A/C systems has a T in it so it feeds to both the front and rear evaporator inlets. You also will need to make sure that the wiring harness for the solenoid valve is in the rear too.

This valves job is to cut off the refrigerant from the rear evaporator when the rear fan isn't on. If the refrigerant kept flowing without the blower on the evaporator coils could freeze.

Also replace the orifice tube from the evaporator at the scrap yard and while the hose on the front evaporator is off replace that orifice tube too. Tubes are only about $3.00 so don't risk it. There is one tube for the front and one for the back don't mix them up they are different colors always insert them with the arrow facing the evaporator.

I'm sure if I missed anything someone will rear A/C will fill in the blanks .

 

Everything that crankshaft said, plus:

The solenoid has to be wired in. One connection is to the Auxilliary Blower Motor Resistor and the other connection goes into the Aux Power Relay to Aux Blower motor run.

What might be more of a problem is the AC duct work. The rear AC has a main duct that runs from the unit up the driver's side door pillar to 3 distribution vents that are in an enclosure running across the headliner. In addition there is a vent near the left rear window behind the driver's seat. Also, there are two vents on the driver's side in front of the rear most seat. I guess, if you don't have that duct work installed you'll have to get it from the wrecked unit. FYI to get the vents in the side you'll have to replace the entire rear driver's side trim panel.

 

My van is equiped with all the ducts and vents just doesn,t seem to have the air core and lines.

 

Well if thats all then just grab the rear evaporator core and lines with the solenoid wiring from a junker vehicle and you should be set. Just pick up a new orifice tube for the rear. You can pick the tube up at either rockauto.com or napa.