I have a 95, and the hvac selector switch is hissing pretty bad in "off" and "max a/c" but otherwise works.

I've tried to pop the unit apart in the past and stopped before I broke anything. I freed the 4 outer clips around the outside of the case but it didn't want to budge.

Does anyone have any tips on this? I assume there would be some o-rings or rubber seals that have failed.

 

I just had mine apart a month ago. And yes, it's fragile!

I only broke one of the tangs, but it didn't hurt it.

Wish I snapped some pictures but I didn't. There is a spring, ball that has to be put back in EXACTLY as it comes out and a small gear. If you dont get it back right, (I didn't....4 times) you have to take it back apart.

Use patience. Also, it may help if it's warmed up some as that may with the clips holding it.

 

So I imagine it's pretty straight forward to open up? Remove from truck, remove *****, release clips and then separate?

I couldn't get the case to budge the first time I tried.

 

I used a small pick set and small, flat head screwdrivers.

It was a challenge popping it open first time, but after that it was easy.