04 yukon p0449 woes

We just bought an 04 yukon last night. It had a p0449 when I bought it, I took my scanner. Anyway checked it out today. Pulled the vent valve, the one above the rear diff and cleaned it out. I was a little dusty, but not dirty especially for 128k. Anyway snapped it back in the bracket, cleared the codes again and started it to continue checking it. I have not 12v power to the unit. The way I read my schematic it has 12v all the time, the pcm activates it by grounding it. I checked the 4ws fuse, the one my schematic shows its powered from and it is fine. 12volts on either side of it, not just looking at it, tested it. So long story short I have a break in the wire somewhere between the vent solenoid and the underhood fuse box. I briefly looked at the harness, very little time right now, and it looked fine. Are there any known trouble spots with the harness to these things? If not my next step is to pull the fuse box out and see if there is a break right under it..

I was hoping I might have a reply or two. I have power 6 or 8 inches from the fusebox then it goes into the big loom all the way back to the vent valve, don't know where it is...

I fixed it after church today. I ended up feeling the harness on top of the tank over to the main harness and could feel a weird place in the loom. I pulled the plastic inner fender out of the left rear and sure enough I could see it. The wire about 16 inches from the vent valve had rodent chews on it and about 1" of what I could see was green from corrosion. I was able to after some trial and error get my hands in there and get the loom clips disengaged and pull the harness out over the tire so I could see it. I cut out about 4" of wire and butt connected a new piece of wire in. Fixed the problem. It always amazes me that people make simple problems so complex, I bet I spent 2 hours mostly to find it, not to repair it and 30 cents worth of wire and butt connector.....

I fixed it after church today. I ended up feeling the harness on top of the tank over to the main harness and could feel a weird place in the loom. I pulled the plastic inner fender out of the left rear and sure enough I could see it. The wire about 16 inches from the vent valve had rodent chews on it and about 1" of what I could see was green from corrosion. I was able to after some trial and error get my hands in there and get the loom clips disengaged and pull the harness out over the tire so I could see it. I cut out about 4" of wire and butt connected a new piece of wire in. Fixed the problem. It always amazes me that people make simple problems so complex, I bet I spent 2 hours mostly to find it, not to repair it and 30 cents worth of wire and butt connector.....
Congratulations! I'm sure there are many of us on the forum who wished we could have been of help but didn't know where to guide you other that to continue the trace.