In my previous request for a 91 manual I was helped by hwin whose post is seen above. He gave me the following link
http://harrywinspear.com/ToyotaHiace/
which appears to be a Gregorys manual and while adequate in other areas its coverage of anything about repairing a broken heater control lever eludes me.
I note that nightdude offers a workshop manual but whether this a Gregorys or a genuine Toyota manual I do not know.