1989 Trooper R/S
Wecome to our Isuzu forum. Blower motor resistor box can be problematic on most of the early Isuzu's. Usually when they fail they only work on high speed. I have an old one off a 90 Amigo. I don't even know if it's good or not or if it might be the same one that's in trucks. Your welcome to it if it looks like it might fit. Located behind glove box..