In the last couple of months, I've started having a couple of issues with my Lowrance HDS7 touch. They may be two unrelated issues. It started out that I quit getting a depth reading on my console unit while on plane and then it eventually stopped reading while idling. The second issue that started up just after that is that my side imaging gives a distorted image yet my bow unit (HDS7 non-touch) works fine. The two units are linked. So today, on the advice of someone, I scanned some bridge columns with the big motor on and viewing the console unit. Distorted images. Then, I turned the big motor off, got on the trolling motor and scanned the same bridge columns and got clear and good images from the bow unit. Also, while scanning with the bow unit, I went back to the console unit and it was displaying normal, clear side scan images. Therefore, I believe the distorted image has to be electrical interference while the big motor is on. Does this sound right? Has anyone else experienced the same thing and if so, how did you correct the problem? I did notice too when I got home that one wire from my bilge pump has come disconnected where two wires are connected by a wire crimp. Could this cause the interference?

Loose connections can cause interference. Check ground wires making sure they are tight and not corroded.

DID YOU BEND YOUR AFT TRANSDUCER MOUNT..?

Check your aft transducer to see if it is clean and has no gouges or cuts in the hard plastic. I hit something on the lake and had problems like you described and I changed out the transducer. I also had a little corrosion in the connection also. Good luck.

My transducer seems to be fine. The interference only happens while my outboard is running. I'll check the wires (and ground). Thank you for your insight!

Make sure all grounds are together, on the starting battery. Clean and tight connections.

I went out again this morning to see if I could try and narrow down the possible interference. Well after trying a few things, it now seems to be that my console unit shows distorted side scan images when my front unit is turned off. As long as my front unit is turned on (whether the trolling motor is in the water or not and whether the outboard motor is running or turned off), my console unit seems to work fine. It's only when my bow unit is turned off that I'm getting distorted side scan images on my console unit. Very frustrating.

My units acted funny when I had low voltage issues. One time it was a battery and the other time was a connection that was loose. You will figure it out with your method of trouble shooting. Process of elimination. Good luck

are you running resistor plugs in your motor!

Actually I'm not sure. Haven't checked. This just started happening just this late Spring (only a handful of fishing trips ago). I have found out that it only happens when my bow unit is turned off. When I turn my bow unit on (whether the trolling motor is in the water or not), my console graph works fine. And I only had my bow unit turned on and the trolling motor out of the water to see if that made a difference in the console unit images.