Okay - I cleaned the connection with electronic cleaner and apply dielectric grease to the connection. The unit is still freezing up at mid day. I contact Humminbird and was told to re-set to unit to factory default and remove sd card and clean to contact on the SD card. I will try to run the unit without the backup SD card ( leaving my map card in). Hopeful this will fix the issue.
Is your unit fine at the start of the day? Is your issue starting later in the day? If it is fine until midday or so, it sounds like a low voltage issue. Humminbird units are notorious for being very sensitive to low voltage. Be sure to check your voltage when you start having problems. Rebooting will usually work temporarily when the voltage is too low but the issue will return. I've had the same issues with my Solix units until I added a battery dedicated to just my electronics. If your unit is wired directly to the battery, cutting off the main switch will not work since there is still power to the unit.
If it is not a low voltage issue, it could be the pins on the power cable are not making good contact. You can bend one of the pins
SLIGHTLY so it makes better contact. Do
NOT bend it too much.