1989 International 9370-GOOD OLE GIRL-Need Help!!

I bought me a 1989 Int. 9370 Tractor. 350 Cummins/9 speed. Going to pull a lowboy around local. Perfect truck for what I need. I've been tinkering with it since I got it 6 weeks ago. Cleaning it it up, fixing light bulbs, changed all belts, flushed cooling system, etc, etc. Went to check AC system, and blowers wont come on. Started looking into it, and found fan switch not to my liking, so I ordered a new switch and installed it. Still no blowers. Took the blowers out and both work. I'm not getting power thru the switch for some reason. Pulled passenger floor out to check all wiring. Nothing found. The truck is a great truck for me. Old school, spring ride, just a good simple truck. But I need my AC, I hate to take it to somebody who is gonna sit there and scratch their head like me. I've checked EVERY connection, fuse, relay, done pull test on harness. Nothing. The harness for the heater/AC box comes across the far passenger side of the dash, goes down the firewall and down into the passenger floor, back to the box under passenger seat. Everything is hooked up and looks good. The weird thing I noticed, the wiring from the blower switch comes off the switch and goes towards the DRIVERS door, which didn't make no sense to me. All electrical is in the dash panel in front of passenger. I pulled dash panels but couldn't really tell where they went. Any help would be greatly appreciated.

 

Int2 by tompands posted May 29, 2022 at 4:38 PM

Int1 by tompands posted May 29, 2022 at 4:38 PM

Int by tompands posted May 29, 2022 at 4:38 PM

 

I was a service manager at Kenworth Trucks for 13 years, worked there for 22 years. I'm half assed decent at electrical issues, but this one has me stumped. The problem has to be deep in one if these 30+ wire harnesses. And one thing I didn't tell you is, sometimes it comes on for a split second. Then it goes back to not working. When it comes on, I have power at the switch, then it goes away. If I had a wiring diagram, I could probably figure it out. Relays are good, Fuses are good. All grounds are good. I hate to rip this whole dash out, but that's what I might have to do. I've done it before, not a fun job. The Power Distribution Boxes in the Kenworths used to burn up and melt. Rewired and rebuilt many of them. About a 12-14 hour job. I have a feeling my issue here is 1 wire,(like a main ground) somewhere in one of these harnesses. But where is the question. I'm going to break out the old multi meter today and see if I can find it. If anyone has a diagram for this old truck, I'd appreciate a copy.

 

ok, I'll try him