I just purchased another lowrance hds 12 for the dash and my dealer is doing the install. Question is, do I need another navionics card, or will the 1 card work?

My current dash graph, as well as the bow graph, are linked together and will also include a link to the ultex I am installing as well if that helps answer this question.

Last, if 1 card is all I need, when I turn on both graphs, do I need to program anything or will I be able to easily put what I want on each screen, such as contour lines on 1 and down scan, sonar, etc on the other?

1 nav card for both. You can set them up to show what you want on each graph on start-up and then adjust to show what you want on the fly.

Need more information. You mention a Lowrance unit and those will share map cards with each other. However you also mention a linking to an Ultrex which leads me to believe you have Humminbird as well. You can't share cards between humminbirds except the Onix and no H-Bird product will share with Lowrance.

kellisag, sorry about that and you are correct. I know the link ultrex goes with hummingbird, but I do have lowrance and just meant that from what I have been told the ultrex can save up to so many spots also so I assumed it was linked to the graphs.

But really I just want to be sure that since my bow and dash mounts are linked, should I only need 1 card.

Hds units will share cards, transducers or waypoints. You will be able to use front graph and see contour lines from the card inserted in your dash unit.

You will have to go into settings on front unit and select what you want to see, whether it be a map card or a transducer. Lowrance tutorial video is on YouTube and is very informative.