Ok, I'm one of the lucky ones that still has working factory air on my '89 D-150. But I'm convinced it could work better. I've been having an issue for as long as I've had the truck, as far as the water not draining out of the evaporator core until I turn the blower off or very low. And when i first got the truck, every time I shut off the air, leaves/debris would come out of the recirc air intake, onto the passenger floor.

As I said my air works, but when I put my hand on the "evaporator box" under the dash, it's cold everywhere except in the middle. So i'm wondering if there's debris stuck in the evaporator fins, to where the majority of the evaporator isn't even getting any air flowing through it.

My thought was trying to inspect/clean out, if needed, the evaporator core, but I can't afford to discharge/refill the a/c system, nor do I want to tear apart the inside of my truck when it's over 90 degrees every day. I'm considering buying an "inspection cover", used all the time on boats. They're meant to be water-tight, and come in various sizes from 3" to over 6" diameter, with a flange that permanently attaches to a surface, and a center section that screws out. I figured I could cut a hole out in the box, and silicone and screw in one of those covers, which hopefully won't look too cheezy or ghetto. I suppose I could paint it black when I'm done. Does any of this make sense or sound reasonable?

 

In the 89 you can remove the blower motor from the engine bay side without discharging the system. This allows access to the part of the box where the leaves tend to collect. The drain tube is also accessible this way. If you need more access I think the front cover plate that the blower mounts to can also be removed.

 

I've taken the blower off before, but can't really get to anything behind it. I'll have to look under the hood and see if I can get anything behind the blower apart there. I'm on a budget but at the same time, I know my a/c can function better if I can get to the evap core. I have gotten loose leaves out of there at one time, but there were tons of debris coming out of the intake under the dash when I first got it. The windows didn't go down when I first got the truck either, so the a/c was always on if the truck was running. So I can only imagine how much wet, mushy, leafy crap is caked onto the evaporator core itself.

 

Well, curiosity got the best of me, so I took my 2 1/2" hole saw to the front of my evaporator box. Low and behold, as soon as I broke through, there was an inch-thick layer of leaves completely caked over the evaporator core. I picked all the leaves out, then washed the core off with degreaser, then dish-soapy water. Forced water, then compressed air through it. My air is now about 8 degrees cooler on average, and I get alot more airflow on hi. My a/c is consistantly around 62 degrees now when it's 95 and sunny out, which still isn't incredibly cold, but the increased flow does make a difference.