I have a 99 W9 with a DDECII that I am replacing with a DDECIV. I underestimated what a pain this would be electrically. Can anyone get me a diagram of the wires that leave the ecm at the vehicle connector? I thought that all the wires on the vehicle connector would go into the cab. Foolish me. So far I have found 1 red wire that leaves the ecm and goes forward to some part of the fan control.
I am switching from a DDECII to a DDECIV. I think the ecm can (does) control the fan on/off. In the new harness I don't see a provision for the ecm to control the fan. Can I put a fanstat in the water jacket and let it run the fan? I know that I will need to figure out NC or NO for the correct operation. That I think is fairly easy to accomplish because we had on/off fans before computers. How do I go about wiring the a/c high pressure switch to make the fan come on when the a/c pressure gets high?
The last 6 of the truck are 584764. '93 Kenworth W9.