[John Wood]

You can get limited access through the evaporator probe grommet. It is a big grommet and to get at it, you just remove the glove box, gently unseat the grommet and pull the probe out of the fins, taking note where it came out.

I actually replaced all the foam insulation around the evaporator using window AC foam strips that I got at home Depot, It is very tight but doable. Watch not to scrape your knuckles.

You wouldn't be able to get a conventional vacuum cleaner hose in there very well, but I took my shop vac and duct taped some 3/4" fexible heater hose to the vacuum cleaner hose to suck out crap on the blower side of the evaporator.

With the insulation job I did, I got the outlet temps to go from the mid 50's (inadequate for a large van) to mid 30's and it will freeze you out with the blower on high. Because of the volume of the van, it still takes a few minutes to cool down those in the back seats since my van doesn't have rear heat.

 

[Honolulu-Hack]

Thanks John, Ill try the custom hose deal. My problem is not enough air volume going thru the vents. It's so grunded up there between the fins I dont think a vacuum will do the job. It used to blow very well, but not any more, and its not the blower and/or resistor issue. But I am going to check to see if replacing the insulation around the evaporator will in fact help. I could be wrong about the whole thing.

 

[ImperialCrown]

Make sure that the air intake screen is in place under the wiper cowl grille. Chrysler used to supply a new one with a new evaporator.
If the evaporator is wet with refrigerant oil, it is leaking and will need replacement, especially if you have to frequently recharge the refrigerant. Some PAG oils carried a green dye to help locate leaks. If the debris has a wet, green tint to it, it may be a leaking evaporator.
If mold and fungus have started growing, they will rapidly create acids that will eat the aluminum evaporator. The odor can be very unpleasant.

 

[John Wood]

I actually had a picture of the evaporator probe grommet that will allow limited access to the fan side (i.e. incoming side) of the evaporator. That big rubber grommet just peels back and you can inspect the evaporator with a flashlight.