I'm replacing the heater core in my 87 4Runner and according to the Haynes Manual I'm supposed to disconnect the heater control assembly.

Now that sounds like a fairly good-sized PITA considering I would have to remove so many parts.

Do I really have to remove the assembly, or just to replace the core?

 

this is a very well detailed walkthrough

 

When I did mine, I did not take out that much of the dash. I did not take off any of the top pieces, like the dash pad or instrument cluster. I just took out a few ducts, the white piece on the front of the heater box, and the heater panel. I was able to carefully pull the heater control box out through the passenger side.