bobcat t300 hydraulic temp sensor error

I have a 2002 t300. it is displaying a "8-21" error code. this is for high hydraulic fluid temperature. the code displays upon starting, and drives the cooler fan crazy. I have replaced everything possible in the way of parts, and am now to the point of chasing wires. there is a single wire that attaches to the temp sensor on the hydraulic fluid filter base that doesn't show continuity, but it is the only wire in the harness that isn't numbered, and I can't find the other end without removing the cab and stripping the machine to the frame. can anybody help? thanks

bobcat t300 hydraulic temp sensor error