Perplexing Electrical Issue, No Radio, but everything else works fine.

J3ff

- Motor has been out and put back in, so anything is on the table.

- If battery selector is set to "combined" radio turns on no problem.

- As far as I can tell all connections appear to be the same as I have a picture from before work was done and the wiring matches up on the batteries. 

- Does not matter if engine is running or batteries are charging or not, same thing happens.

- Batteries did need 1/2 gallon each of distilled water before they were full again (keep in mind even with the crazy low water situation they still started and ran everything just fine)... 

- All 12volt lights in the cabin work as expected as well. The only weird thing is that the strip lighting (ebay) when turned on results in a weird humming noise coming from the wood LED lights that I got from Diggin... even when they are off. Not sure if that has anything to do w/ it, just saying what's going on. 

Here's where I start to get confused.

If you take an LED and plug it directly into the wiring harness plug that goes into the radio, it lights up just fine, in any battery selector position (other than off of course)...



I have purchased a new radio and it behaves the same way. Only runs on combined mode. 

Normally I'd think it's some kind of voltage issue, but if it was that, how in the world do the batteries have enough power to start the boat/run the hatch motor/run the fresh water pump, etc etc etc... 

Anyone ever run into anything like this? 

Lake_Bum

It is possible, that somewhere in your wiring for the stereo, that something is backwards on the + - connections.  LED lights, will work regardless of polarity, so that test could be messing with the results. 

PickleRick

Led lights run stupid low amps.  Use a multi meter and measure true voltage at all 3 battery settings

J3ff

PickleRick said:

Led lights run stupid low amps.  Use a multi meter and measure true voltage at all 3 battery settings

Yeah, have one at work, will bring it home tomorrow. The only thing is how are these batteries starting a motor and running much higher amp devices and they can't power a radio... there's no external amp either. 

J3ff

Lake_Bum said:

It is possible, that somewhere in your wiring for the stereo, that something is backwards on the + - connections.  LED lights, will work regardless of polarity, so that test could be messing with the results. 

If that were the case, why would putting it to combined fix the problem. At first I assumed they just messed something up putting the batteries back in.. but a very close up picture taken weeks before they took the motor out shows it being put back exactly right. 

J3ff

Okay. Narrowing it down. The goal here is to figure out why the Red wire (remote 12v) that tells the radio to turn on is only getting power when 2 things happen: (for my LED test I was hooking it to the yellow wire.)

- Battery is turned to combined
- Key is turned left or right 

J3ff

Whatever they changed it appears that something was wired incorrectly before and is at least 1/2 correct now.

I realized that for the past 3.5 years the yellow wire and the red wire have been reversed as far as the diagram above shows.

HOWEVER. Now that the radio turns on when expected. It will only have enough power to play sound through the speakers when turned to the combined.

When selector is turned to battery one and key is turned on = bright screen no sound, but battery cannot start engine. This is supposed to be the starting battery. 

When selector is turned to battery two (two group31's in a series) it turns on, pulses brightness and will not play sound. However battery 2 successfully runs everything else on the boat and starts the boat just like it has since I bought them 3.5 years ago. 

The moment you start pushing it over to combined, before it even clicks, sound starts playing through the speakers. 

How can battery two have enough power to start the boat but not enough to get sound through the speakers.. crazy.

Either way sounds like three new batteries are needed. 

Battery 1 is an optima starting battery, Battery 2 are two deep cycle batteries.. 

aero3113

What does it do with the charger on?

J3ff

aero3113 said:

What does it do with the charger on?

same result. also same with engine running. 

reneechris14

What about the amp?? Bet the wire the amp is on battery one??

reneechris14

J3ff said:

PickleRick said:

Led lights run stupid low amps.  Use a multi meter and measure true voltage at all 3 battery settings

Yeah, have one at work, will bring it home tomorrow. The only thing is how are these batteries starting a motor and running much higher amp devices and they can't power a radio... there's no external amp either. 

There should be an amp above the radio??

J3ff

No amp. Removed that when I first got it. Ran 3.5 years with no problem. Either the batteries are now crap (after sitting for 6+ months with half water) or they missed a ground or something? 

reneechris14

All the gounds go to a post above the starter on the bell housing.

reneechris14

Same problem when on shore power?

J3ff

reneechris14 said:

Same problem when on shore power?

I assume so, but need to verify again. 

J3ff

Yes, same exact behavior on shore power with battery charger turned on.

I cut the ground to the radio and ran it through the ground for the cigarette plug.. same problems. I guess the next step is to run a ground wire directly from the battery to the radio and see what happens..?

J3ff

Well this one is "solved" - but not really.

I guess filling the batteries back up with water and letting them (all three of them) charge overnight was all that was needed. 

Today after 18 hours of charging the radio operates exactly as expected. 

Still doesn't explain how a battery can start a motor, run all other items, but not run.a simple radio. Will get a battery tester and see if they need replacing. 

Aqua_Aura

May be a weak connection to the stereo so it needed strong batteries. Engine is gonna use larger gauge wiring and may be less picky to lower power. Just a thought. 🤷🏽‍♂️

I had an amp issues intermittently powering and it was just a loose connection on the amp on a screw that needed tightening. Point being it all may look correct but make sure you check everything. 

MarkB

Well, it might simply be a minimum voltage protector.  My fishfinder/sonar had that ... if voltage dropped below I think 11 Volts, it would cut off ... to conserve battery power for the engine/emergency systems.