Our GPS speedo does nothing. It will not come off of 0 . For a while, it would jump up to 15 or so when you hit recall, but it doesn't do anything right now. Any thoughts on what could be the issue?

Dead battery in the receiver. Look here....

http://www.offshoreonly.com/forums/g...ps-speedo.html

Personally, I would forget about changing the battery and wire the speedo to your GPS. Never have to worry about it again.