Boat battery charging issue

A solid yellow light on Bank 1 of your Minn Kota 315D 3 bank charger indicates that the charger is in "float" mode, which means it is maintaining the battery's charge at a safe level. It sounds like there may be an issue with the connections or wiring for Banks 2 and 3, preventing them from receiving power.
Here are a few things you can try:

• Check the connections between the charger and the batteries for Banks 2 and 3 to ensure they are tight and secure.
• Ensure that the circuit breaker for the charger is not tripped.
• Check the wiring for Banks 2 and 3 for any visible damage or corrosion.
• Ensure that the batteries for Banks 2 and 3 are not in a low state of charge or are not faulty.
• Try to reset the charger by unplugging it from the power source and plug it back in after a few minutes.

You can buy a (Battery Switch) that controls all your batteries. Where ever you turn the dial is what bank you will be using.
As far as The trolling motor go get a three prong plug, female male ground and stand by. The wiring is so simple it you do this.

Walld"

By reading this.. I am assuming #3 is the crank battery....

Try this.. (from experience) remove all wires (or big terminals) from the battery and see how that works.. I have a 3 bank and use a stand alone charger!! Works BETTER!!!

Do you remove the trolling motor wires before charging..? ...If not.. try that......mine started taking a LONG time to charge.. after I remove the trolling motor cables.. it take less time and charges better!!!

Smart chargers will fail to charge completely discharged battery. Simple charger w/o electronics will. Try connecting two batteries together with charger. ALL in parallel. + to +, and - to -.

2 bank battery Minn Kota System wiring diagram Google Search

Connecting dual bank charger to 24V trolling motor General Discussion...

2 bank battery Minn Kota System wiring diagram Google Search

Hello Brad / Colee

The voltage converter in the charger has gone out (violently). Do not use this charger in your craft anymore. There is no longer any kind of guarantee of isolation, and galvanic corrosion may be accelerated if the boat is sitting in the water and you try to charge batteries.

Replace the charger. Your craft and your lives aren't worth the risk. You can try contacting Minn Kota to see if there might be some kind of warranty assistance.

does anybody fix minn kota 3 bank chargers

First. the +/positive/hot wires go to the respective/separate +positive/hot side battery terminals.. and the -/negative/ground wire go to their respective/separate -/negative/ground battery terminals.
The wires from the charger are "paired out".. meaning the + and - pair must go to the same battery. .. you can't mix and match.