85 340 - dashboard gauges tarboard engine short out/what is this device?

[Bill Gau]

Hi
I was testing my engines and electronics getting ready to put boat in the water. with the engines off, when I turn on the nav lights the starboard engine related gauges no longer light up and all the gauges pin to the right. any ideas? also, can someone tell me what the device is in the attached image. it is connected to the battery switches and has a heat sink. Is it related to the battery charger? thanks

 

[dwna1a]

Bill it almost looks like a old inverter. I will look at my neighbors 34' when I get to the boats. Maybe he has one as well

 

[Bill Gau]

Great thank you

 

[Chris-380]

Looks like a battery isolator to me

 

[RollerCoastr]

Looks like a battery isolator to me

Me too.

 

[Chopperdr.]

Battery isolator for sure