OK, It should be the OLD Heart ECHO charger. The company is now Xantrex but they still make the charger. It is very simple--3 wires
Connect from the echo-charge:
• Ground wire (black) to the negative battery ground.
• Starter Battery wire (red with yellow trace) to the starter battery
positive (+ red) terminal. A 20 amp fuse in this line protects the wire.
• House Battery wire (+ red) to the house battery bank positive (+ red)
terminal. A 20 amp fuse in this line protects the wire.
IF you have 12 volts plus on the RED and the RED/Yellow trace AND Ground on the Black, and the unit does NOT function. It is bad and must be replaced. There is a fuse INSIDE the module but per Xantrex it is a factory replacement which will cost MORE than a New Echo charger. About $100 on line at various websites. Doug