Ok, so there appears to be two separate issues, correct? 1) Both Bow and console HDS units which are wired directly to the battery will not power on. 2)Fuse for electronics which runs to the terminal board at the console keeps blowing.
For issue 1, Using a volt meter measure battery voltage. Then take the meter and measure the voltage on the pins 7 & 8 (the two larger pins in the female connector) of the HDS power connectors and confirm that you have at least 12 vols present. Below is a link showing the connectors pinout. It is near the bottom of the page.http://support.lowrance.com/system/selfs...ID=2141#mapping