Works on down scan but not on sonar

Yes, I prefer to use transtricers, three is the charm.

Water depth should show automatically on your sonar page.
if it does not then either you have selected "stop sonar" under your sonar options or you have opted to turn off the depth displayou so the numbers don't show up.
if you areally viewing your GPS or split screen sonar/GPS page, sometimes the depth display is not visible on these pages unless you specifically instruct the unit to display it.
Lowrance HDS 5 Gen2 Fishfinder GPS Chartplotter
Here is a link to Lowrance where you can download a pic version of the operators manual.
Go to page 11 "overlay data" this will give you a step by step of how to add data or readouts to different screens.

I don't have the same model but the same issue before the cable from the sonar was frade some and so it wasn't sending a good signal to the box so it just said loading I had to replace the sonar and then it worked fine

ooooooooook click menu button twice go to functions scroll down to structure scan see if the circle beside it is high lighted if not click on it to turn it on do this to both units

don't quite understand what your saying far as the question..when you click the page button on your unit does it show structure scan on the page and if so you go into structure scan and its not showing structure on the screen ?? maybe you need to (fine tune ) your unit or check your transducer to see if its working

verify cable harness integrity at base connection of transducer , replace cable or check settings easy fix would be change display unit if unit under warranty as replacing transducer is not easy and economical

I have the same problem on my 520C.
I have no solution but I hope you have find some?
Best regards
Dan

(1) bad transducer. (2) bad ground from unit to battery. The cable next to the battery will have no effect.

Go into your gps settings in the menu and then select "Initilize GPS". That will basically reset your GPS and it should find your location. It can take up to five minutes so initilize it and crack open a cold one. when you get back your location should be on the screen.