aprs interference with instruments

I have a mt8000fa installed in my wing tip on my rv7. I have a seperate circut and ground wire to the unit and nothing else on the circut. When I turn the unit on, the oat on my efis starts going wonky? Any ideas? the power and ground wires are not shielded.

I was thinking(that usually hurts !!)is there some type of filter that could be installed on the power or ground wires, or both, to remove the interference?

Aeroelectric makes a filter that may help...

How about one of these? The -99 version includes a full filter to remove any electric noise. It's originally designed by Aeroelectric Bob to power LED Nav lights, but can be a filter for other electrically noisy equipment as well...

I have two of these for my LED Nav Lights and they work great removing noise, but can't vouch for APRS noise.

https://matronics.com/aeroelectric/Catalog/AEC/9051/9051-700A.pdf

1.0 FEATURES
1.1 The AEC9051 Series LED driver assemblies were
crafted to offer the OBAM aircraft owner a means by
which the popular ?Buck-Puck? by LED Dynamics could
be integrated into a noise free, do-it-yerself LED
illumination project. The stand-alone Buck-Pucks are
reported to generate considerable radio noise in the VHF
Comm band. These would certainly be a problem for VHF
OMNI radios also.
1.2 The AeroElectric Connection crafted radio noise
filters for both the 14v input and LED output leads and
assembled them onto an etched circuit board

Good luck!