The magnetometer is far more sensitive than the autopilot servo. The Garmin instructions recommend using shielded wire for the pitot heat (high current draw) with respect to the magnetometer. You can find this wire at edmo.com. Some folks twist the pitot heat wires to reduce the chance of noise without the shield. My bet is you won't have any problems if you just run straight, regular wire especially if you have the pitot tube that does not have the controller. But, I try to follow the Garmin instructions to the letter....the only thing in their instructions that bother me is how they ground shields at multiple locations and at both ends sometimes.
Ellis
A&P/IA
Fayetteville, NC
RV-7a Builder, Grumman Tiger Owner
Dues Paid