S3 Auto Pilot "Drivestop" error

[RichardTaylor]

My Raymarine auto pilot has stopped working and after approx 1 minute gives "DriveStop" message. I have checked all the fuses on the course computer and they are all fine. I can hear the clutch engaging and the wheel locks.

I have 12v input to the S3 but the one thing I am not seeing is any voltage across the "motor" terminals (even when adding +10/-10 at the pilot head). I do get 12v across the clutch terminals when the pilot is engaged.

I can see the rudder position changing on the pilot head when I turn the wheel.

Any thoughts on what is causing the issue (everything had been fine 3 days earlier)

 

[Ian_Edwards]

Since no one else has replied, I'll add my thoughts.
It a long time since I had an S3, but I think it has 2 sources of power. A low power supply from the Raymarine bus, and a seperate high power supply to the motor.
It sounds like you have lost the high power supply. This supply will be fused at 25amps or more. I'd look for the fuse first and check it.
If that OK try checking the wires to the motor motor controller and on to the motor.
If that all checks out them it gets more complicated, and I'd get some outside help how understand the system.
Getting and installation manual would help. These are available on the Raymarine website, probably under legacy systems.