Humminnbird/Minn Kota Problem- Not playing nice

I posted this on another site, a member recommended trying here as well….so here goes.

Ok I’ve gone round and round with both manufactures, dozens of calls, work and effort, with out a solution. So I will see if anyone here can help me. I purchased a 788DI for the front of my boat, works great until you engage the trolling motor. I have the transducer on the bottom of the lower unit. When I engage the trolling motor, the depth goes crazy, and the sonar and DI screens fill with electrical interference. Trolling motor is a Minn Kota Maxxum 80 24volt with US1, think its a 2005 or 6

Things both manufactures and I have tried:

Disconnect US1 at the head of the trolling motor
Yes the fish finder is powered by a separate battery
Isolate trolling motor power cables, I ran them through a rubber conduit.
Move trolling motor power cables to the other side of the boat
Ground trolling motor battery to main battery
Ground from skag on trolling motor to trolling motor battery
Humminbird sent power cable for the fish finder with a filter on it, think they called it a choke
Placed a piece carpet between transducer and lower unit
Replace metal clamps with zip ties

When I move the transducer 6 inches away from the lower unit…no interference shows on screen.

Thanks to anyone in advance who may have any suggestion to relove this issue.
Just fyi…..old fishfinder was a Eagle that was US1 compatable…so never had a transducer on the lower unit itself.

Easy fix. Call Humminbird customer service they will send you a trolling motor interference kit (free of charge) with some chokes and ferrite rings. I had the same problem and with the kit installed all interference is gone.

There is also a small fuse inside the head unit of the trolling motor that if that is burned out will add to the interference but my fuse was fine and the intereference kit solved the problem.

Are you saying the trolling motor has US1 but your not using it? Using the transducer from the Hbird unit?

My I-pilot spot lock would not work correctly until I moved my Humminbird GPS antenna to the back of the boat. I have a Humminbird 798 mounted on my Minn Kota Terrovo and have had no problems with the depth shown. No everything works fine.