need guidance toward AC/Heater "nightmare!"

[Prock~1338]

First and foremost this is my first post so hello to all and thank you for all of your time taken to answer questions, post your projects and help the next man with a problem that he may have had to spend untold amounts of money to fix the issue! So my hat is off to all!

So I have a new to me 1998 Explorer Eddie Bauer 5.0L with 91,000 in incredible condition for $4500 - I am extremely happy with it so far, unless you count the typical problems associated with the 5.0 - First and most annoying is the constant tick of the manifold crack (I am waiting for Jeff I think his name is, from TorqMaster Headers to get up and running again - counting the days!) Next and it hurts me to even type it but the horrible, ridiculous gas mileage it gets under normal driving conditions and freeway best my instant mpg has ever shown was 9.7.The only other thing is unique to any other explorer I have ever seen and I have been a service adviser -but it has both front and rear Air Assisted shocks. I cant tell you how many pairs of these I have had to take out of the rear of Expeditions and replace them with coil springs. Real miracle is that this particular Explorer's Air Assist system actually works...... Its a miracle to me, but it will not be in the vehicle for long. Anyone interested in any part of the system, let me know

Now the problem! I live in San Diego so A/C is an absolute must. When I bought the car I noticed it had some sort of digital automatic set your degree and its supposed to do that. From the start there are two choices 1. push Max AC - turn the fan all the way up and pray for cold air. Every other button on the dash like vent, floor and panel , once pushed shoot out "almost fire!"
I took it to a shop that focused on A/C and he basically scolded me for adding too much of the Autozone fill it yourself bottles. He said he sucked out all the old and then filled the system to the proper amount. From there it got colder for a the meantime but he said the compressor is working fine and he didn't have anymore time to dig any deeper into the system to see why I was only getting hot air on every other setting, however I did hear him say something about a "Mixture Door" or something - after reading several posts I dont know if this would fix the entire issue, but it probably couldn't hurt to replace mine.

- Does anyone know a reputable AC/Heating shop in the San Diego Area?

Any and all information is greatly appreciated!

 

[Turdle]

The heater core and AC evap core are in the same box.

The "blend door" is a duct flap which directs air over the heater core, or evap core depending on whether heat or AC is selected. If it stops, it could be half way between, or all the way over to the heater core side.

Search for "blend door" and you'll find several threads on this issue.

 

[TestPoint]

Another simple bypass of the problem is to install a valve in the coolant line to the heater core. In years before blend doors it was a common solution to heater valves that leaked hot coolant through the system. A simple 5/8" male to male valve is available at most any hardware store or auto parts store. Simply cut the heater hose and install with a couple clamps.