9641 Brake problems

We are having a multitude of issues with our 2002 Forterra 9641, currently most critical is brakes, or lack of.
I crawled under the tractor and looked at the air tank and saw a yellow wire disconnected coming from the same harness as 2 green wires that connect to a small unit on the side of the air tank. I looked at a neighbor's similar tractor and the yellow wire connects to a wiring T on the side of the brake mechanism. Nothing similar exists on ours. Any ideas or suggestions?

i think thats the wire for the low air pressure switch. you dont need to have air to have brakes. the brakes are hydraulick. so if you dont have brakes check the brake fluid reservoir. and try to bleed the system. its an easy way to see if this wire is for the pressure switch. just let the air out of the tank and see if the low pressure light on Dashboard comes on.

Hi,

That wire should be connected to each of the brake pads on the cardon shaft brake disc. It is there to let you know when the pads are nearly worn out.

Mike