Wagner MP320 Autopilot Shut Down

[eggman]

I was motoring along during a mild electrical storm with a heavy load on my 12 volt system. When I turned on a cabin light I heard a small beep from my pilot and it quit working. The rudder did not change position and the display was blank but still lit.

I turned it off then back on. The display showed 8888 and stayed there. The dodge buttons made proper beeps but did not move the rudder. Tried to re-set system but it would not respond. The fault code menu could not be accessed. I cleaned all the connections and the circuit boards have no obvious damage. I also disconnected cables to the motor to my pumpset, and applied 12V directly, that moved my rudder, in both directions. The motor control to the pump-set checks out. The fault seems to be either in the control head or the nav/junction box and possibly the flux-gate compass.

[GordMay]

Yes, the fault may be low voltage, or (as you suspect) in the control head or the nav/junction box or possibly (but less likely) the flux-gate compass.
The "heavy load" may have produced a severe voltage drop.

[eggman]

Thanks for answering my post. I guess there isn't an easy method for testing outputs of either the control head, nav/junction box or the flux-gate. It may come down to testing individual components on the circuit boards, but without a schematic, it would be like looking for a needle in a haystack.

Gregg Richard