Struggling with the search function...

Anyhow, my rear AC won't work despite the front AC working well. Searching tell me it's likely an expansion valve, but, well, this is my first AC endeavor and I could really use some sort of diagram to guide me! Anybody got a line on the '89 manual or could confirm the '87 AC system might be the same? I did find an '87 manual.

Thanks for any insight!