Why did you go immediately to the actuator at the control valve? There is a switch inside the handle on AHCS machines that will fail (from what I've seen more often than the electronic actuator at the control valve) If your diagnostics don't work, I'd take it to a Bobcat dealer and pay the $50-$100 depending in how good your dealer is and have them plug it in and run a check on it. In an hour they should be able to diagnose and give an estimate. It could save you some time chasing your tail and in the end it could save you money if you wrongly decide on a part, replace it and the don't fix the problem. BTW, a service manual is worth its weight in gold if you plan on working on the machine yourself. There is a calibration process for the switches inside the handles.