859 shutting off

Bought a brand new 859 had it out 3 times. Now when I turn it on it shuts down. Then starts back up then shuts off again. And wont turn off til I unplug it. I hook up my 998 to the wires and it works. Hook the 859 to the 998 wires and it shuts off. So the problem is in the unit. Any ideas guys? Hummingbird hasn't been much help so I figured I'd try here. Thabks

I don’t think that there is any more help in troubleshooting this as you have done well to the point that you know it is something inside of the unit that is causing this. Call the Humminbird Customer Resource Center folks about getting your 859 unit into the factory to be fixed.

Thanks for the help.