Help required TMQ AP46 auto pilot

[rustymarlin]

I have an ap46 auto pilot that is not playing the game correctly,the heading continually changing while travelling in a straight line so much so that the auto pilot disengages I have disconnected the electronic compass and the unit goes into fault , when it is connected and sitting in the driveway the heading moves around 30 degrees any ideas

[scottar]

You have a faulty compass by the sounds.