Problem with Coursemaster autopilot only on certain cardinal directions

[svstrider]

I have a Course master autopilot. If I am heading east or west it gives a compass fault error message and heads off course. This was no problem on the east coast of australia but now that I am heading east to the Pacific from Sabah it is a real PITA. The fluxgate compass is located near electrical wiring including the battery wires BUT it still happens even if the engines are not on.

I have put conduit around all the wires. I have moved all metallic objects away from the compass. ALSO the manual says the problem occurs only on certain directions because of magnetic fields. ALSO the compass is mounted upside down which is should not have been. When I mount it right side up the autopilot does not work at all. ALSO manual says that the feed wire from the CPU must enter the unit from the port side. However if I mount it right way up thecable enters from the right side of the compass. There is a stricker on the compass that says the bow direction must be in the direction of the arrow n the sticker. The only way to have this happen AND have the feed wire coming into the compass from the port side is to mount it upside down!!!

Suggestions gratefully appreciated. No way to send it to the manufacturer. I am in Sulawesi, Indonesia.