Magnetic Anomaly G3X GMU11 GSU25 Garmin installation

[ThorLasVegas]

Hi there. So I installed the GMU11 in the tail section accessing it through the fairing around the rudder base. The magnetic interference test checks out fine but I get this during flight! Any ideas? How hard is it to get the wire out to the wing instead?

 

[Avanza]

Hi there. So I installed the GMU11 in the tail section accessing it through the fairing around the rudder base. The magnetic interference test checks out fine but I get this during flight! Any ideas? How hard is it to get the wire out to the wing instead?

Before moving the magnetometer, this could well be interference from electrical wiring close to the magnetometer or it's wiring.
If this is the case, you could wrap the wires with aluminum or copper tape to shield them from external interference.
Wires to servos, nav lights, fuel pump or strobes may cause interference. Com antenna can radiate strong fields but only during transmitting.
Where is transponder antenna located?
Have you seen this warning during taxing or flying with most electrical system in the off position ?
I would try turn most electrics off and then turn them on one by one. If this doesn't help, try to move the magnetometer a few inches away from nearest
steel parts.

Good luck