Hey all. I've done the search on this several times, but so far have come up empty. 94 aero awd 57K miles. Air blows cold out of dash vents, but is warm coming out of rear cabin vents. Does anybody have any ideas where I should start? Maybe it is not common as search turned up nothing? Any help would be much appreciated.

 

Here's a link to same problem. The search feature is not often very helpful. This may offer some insights to your problem. If not, we are always around and ready to help.
https://www.ford-trucks.com/forums/4...-aerostar.html

 

Thanks, that gives me a good starting point.

 

There should be a vacuum operated blend door controller for the rear. Maybe the vacuum line is broken or disconnected. The system is designed to default to the defrost position if anything goes wrong.

 

Thanks, Bear River. Are there vacuum lines going all the way to the back, or is the blend door up front?
You have 195K on yours? Looks like we have about 140K to catch up. lol
We have had this Aero since 1995, but it sat in the garage for the past 8 years. Had to put a new sending unit/fuel pump in it, changed all the fluids, a new battery and it fired right up. Runs like brand new. Got some electrical gremlins though. Need to put a new clockspring in it. P. brake and ABS lights are on all the time, and the intermittent wipers are real intermittent. I'll get it all straightened out though, one friggin' thing at a time.

 

RS,

There is a vacuum line all the way to the back vacuum motor. You will need to pull the panel for access (not just the vent grate). If someone has already been back there working, it is very possible the actuating arm for the blend door is just disconnected from the vacuum motor. When I worked on mine, it was real tricky to get the arm to stay on while buttoning up the unit. If the motor does not activate when the rear A/C is selected, pull the line and test both motor with a length of tubing and slight suction and also see if the vacuum line itself has active vacuum.

The entire rear HVAC unit is pretty simple in design and operation. There is an A/C solenoid you will find near the bottom middle buried under padding and insulation. If you hear/feel it click when the control for rear A/C is activated it is likely working fine. These are normally troublefree units. The only possible problem would be a plugged orifice tube inside the solenoid valve. These would only plug if the A/C system suffered the dreaded 'Black Death' syndrome.

 

Ahhhh, starting to make sense to me now, thanks a bunch.

 

Well the blend door moves up and down when I switch from A/C to FLR, so vacuum must be fine. Guess I'll tackle the solenoid next.

 

Don't forget that the A/C vents (in the roof duct) will only become active when you actually select the A/C function. They will not work in any of the other modes.

 

Yeah, they just blow non cooled air in a/c mode. Could this be a low coolant situation? Front blows ice cold .

 

put a set of A/C gauges on it. the pressures High and Low will be the same in the system front and rear if the accumulator/dryer, black can filter mufflers and orifice tubes aren't plugged. the accum/dryer for the optional front/rear air rigs has 2 outlets.
will quickly tell you if low on R134a which the 94 model came from the factory with

the rear ac unit has at least one of the black can muffler filters. they do plug
the rear a/c refrig. control valve can plug also. plunger may partially move and make noise, but no r134 flow.

 

Ok thanks, will be a couple days before I can get back into it. I'll report back. Thanks again all.