I ran across this post while troubleshooting my HVAC Auto control unit. It had gone completely out. No fan, no position lights, no air duct control. Dead as a door nail except for backlighting. Thought I would post what I found, in case someone else runs across this post.
The shop manual identifies a relay, labeled X-6 and a fuse, labeled FL-1 that should be checked if the unit is not working. There is no relayed labeled X-6 nor any fuse labeled FL-1 in the car. That must be a technical writing nuance that I don't understand. However, there is a heater relay in the engine compartment fuse box labeled EB-25. I believe FL-1 really refers to "fusible link" 1 that runs between the Heater Relay and 10 amp fuse E-5 in the same box. The fusible link runs underneath the fuse box from the EB-25 to E-5. Fusible links are insulated wires that are intended to burn in two, like a fuse, before damage occurs to other components. I am unclear why these are used instead of fuses themselves. Given how tight the wiring is on the back of the fuse box, it would be quite a chore to have to change the fusible link. But I digress. I found that my heater relay had fried. There was melted plastic on the relay and the fuse box. Also smoke residue on the cover of the fuse box. Ordered a new one from Jack Miller Isuzu here in Kansas City for about $35. It solved the problem. For those doing troubleshooting, the heater relay is the same as relay EB-27, just to the right. If you think your EB-25 Heater Relay has gone bad, temporarily swap out EB-27 to test it.
Hope this helps. I'm slower than most, so this took some schematic reading and pondering before I could find the simple relay and fusible link that are mis-labeled in the shop manual.
Jason
Jason White
2001 FoxFire Red VehiCross