Denso dash a/c heater problems

[L Luebcke]

2006 American tradition with spartan chassis. Same problem as some others? Drove rig from Denver to Phoenix over Christmas. Heater worked fine, turned off engine for 3days then started to go to california and no heat or a/c. Blower will not come on. 2 separate tec,s have checked every circuit and even replaced main control box ($550.00). Still nothing. Can anyone tell me what is wrong? I'm at a dead end. Denso can't answer my questions, we tested everything they told us to and nothing?? Help

[UsualSuspect]

Not sure if this will help or not, but there is a 10 amp fuse located on the wiring harness in the dash. Look at post #10, download the file and explains where it is.
http://www.irv2.com/forums/f258/dash...ml#post1600772

You can also download the schematics and service manuals from Denso. They are located here: HVAC Systems | DENSO Heavy Duty

Good luck, post back if you find the problem, I am sure you will not be the only one, and will probably save someone else a lot of grief.

[98FPA]

I had a similar problem on my 98 Pace Arrow. No a/c heater blower, one day it was working and about a hour later it did not work. My problem was the relay for the blower motor which was located behind the passenger side kick panel. The relay for mine was the typical 5 pin relay sold at my local parts house, relay cost just under $10.00. The relay in question is just behind the a & y in the word relay in the attached pic.


Mine was a Denso hvac system but it may not be the same. I found the fuse that was mentioned but that wasn't it, mine also had another fuse in the kick panel area. The schematic mentioned above was an excellent source for me, actually led to the problem relay which for some reason I had completely overlooked. Good luck.