Transducer comm error when connected to bus bar

[Jimmyjudd66]

Hello electrical gurus. 23’ ar195

I recently added a new 250amp negative bus bar by my single battery. The intent was to move every ground but starter from battery. In the battery compartment there already was a full factory bus bar in place. So what I tried to do was add cable that originally was connected from battery to factory bus to my new bus. And then connect my new bus to battery. (I.e. Battery> new bus> factory bus)
When I do that my fuel gauge shoots to 100% and my factory transducer and cruise control quit working.( I get the Transducer comm error and alarm on the dash)

If I reconnect the factory bus to the battery negative all works as it should. (I.e. battery > bus 1; battery > bus 2).

Can I not go bus to bus for ground wires? Currently the only thing connected to new bus bar is the factory house harness that controls the connect screen, dash switches, and stereo. All of those function as expected regardless of above.

 

[tdonoughue]

What size and length cables are you using? You may be adding just enough resistance to drop voltage...

 

[Jimmyjudd66]

What size and length cables are you using? You may be adding just enough resistance to drop voltage...

What’s odd is I went 1 ft. Of 2 AWG.
Technically 2 ft total addition of 2 awg (1 from battery to new bus, and 1 from new bus to old bus)

 

[tdonoughue]

Might try 1 or 1/0... I would think 2 would be enough, but really depends on how many amps you are drawing. Do you have a meter with a clamp? You can measure the amperage in the working configuration to determine the size. If you are over 115 amps or so you may need to size up.

 

[Jimmyjudd66]

Might try 1 or 1/0... I would think 2 would be enough, but really depends on how many amps you are drawing. Do you have a meter with a clamp? You can measure the amperage in the working configuration to determine the size. If you are over 115 amps or so you may need to size up.

What baffles me is even if the amp is disconnected, merely having the wire itself connected causes the problem. I have a multimeter. So you’re saying measure the overall draw while everything is going correct?

One thing of mention too. I did install the blueness 2 battery isolator switch. Currently only 1 battery connected though. Not sure if that’s related in any ways but something to note.

Again if I remove the new ground buss I added then problem disappears. I even tried running new buss and old buss to battery neg separately and still get the same problem.

 

[tdonoughue]

Depends on how it is wired, but I would not think the isolater would do anything here.

Yes, I would measure how many amps are coming from bat to each bar. When you wire it as you want, you are pushing all amps through the first wire, which may be too much.

And pics while you are there of your setup, please.

 

[Jimmyjudd66]

Depends on how it is wired, but I would not think the isolater would do anything here.

Yes, I would measure how many amps are coming from bat to each bar. When you wire it as you want, you are pushing all amps through the first wire, which may be too much.

And pics while you are there of your setup, please.

Hey thank you for trying to help. So I didn’t get a pic yet but I did A LOT of troubleshooting last night and I found out I was wrong. My grounds were not the issue.

When I connect the power lead (+) wire to my circuit, I get the trans comm error and my fuel gauge shows 100%.

What’s crazy is even if the other end of the 8 ft run is not connected to it touching anything, it causes the problem. I ran the wire where it’s away from everything else so I’m not sure why having the wire connected causes a problem. Again this is not even being connected to my amp which is what I ran the wire for. I used OFC tinned copper 4 AWG.

What also is driving me nuts is after I disconnect the positive lead I added the issue persists for a little while sometimes I have to remove battery connections and re-add them. My terminals are lean. Battery is almost new. I’m wondering if my connext is the problem and is just bugging out

 

[tdonoughue]

I'm wondering if when pulling it you scraped off some insulation and it is shorting on something.

I would pull that 8ft. If there is something sharp in the path, it may have stripped something else and be causing your issue. Just connecting to a wire capped at the far end should not do anything...

 

[Jimmyjudd66]

I'm wondering if when pulling it you scraped off some insulation and it is shorting on something.

I would pull that 8ft. If there is something sharp in the path, it may have stripped something else and be causing your issue. Just connecting to a wire capped at the far end should not do anything...

Another update. I was out of town for a little bit visiting family. I appreciate your helping me with all this.

So I undid all the amp wiring etc and the transducer error went away. Well today it started up again. This leads me to believe that the issue is unrelated to the amp and merely messing with the wires was also happening to set it off.

I had installed a 2 battery blueseas battery switch at the same time I wired up the amp, and I’m wondering if my connections are loose at the switch or maybe the switch is bad/causing resistance in the circuit and are affecting certain more sensitive compenents. Namely transducer. Fuel gauge. No wake mode. Cruise control.

Sometime when I cycle the battery switch off and on multiple times the errors go away.

Any suggestions on how to successfully trouble shoot this?

 

[tdonoughue]

Was everything working fine before the switch install?

I have made the mistake many a time at looking at all sorts of things other than the thing that I just put in (perfectly--I remember, I did it perfectly), only to later learn of a problem where I put that last thing in.

Any changes you recently made to the boat whereupon the error started happening are suspect, no matter how remote/safe you think they are from the issue. Begin by double checking all of that. With the switch, confirm not only good connections, but good crimps, that the wires are going the right place (haven't crossed positives or anything), etc.

 

[Jimmyjudd66]

Was everything working fine before the switch install?

I have made the mistake many a time at looking at all sorts of things other than the thing that I just put in (perfectly--I remember, I did it perfectly), only to later learn of a problem where I put that last thing in.

Any changes you recently made to the boat whereupon the error started happening are suspect, no matter how remote/safe you think they are from the issue. Begin by double checking all of that. With the switch, confirm not only good connections, but good crimps, that the wires are going the right place (haven't crossed positives or anything), etc.

Everything was functioning fine before swapping the switch yes. I’ve only owned the boat since November last year (it’s a 2023) and I took it out probably 10-12 times before swapping the switch without ever seeing the issue.

Now that i think about it, when I added the positive bus bar, I had the intent of moving every positive cable from the oem switch to my new bus bar (2 factory house cables) only to find that the constant hot for the bilge pump was loomed together with a switched positive and therefore one of the 2 cables had to be left. I then added a new 2 awg positive cable from switch to that new bus bar and then connected that remaining switched power cable to the bus bar. (This is the same bus bar the power cable I was running to my amp was connected).

Do you think having the 2 house cables at different contact points might be causing the issue?

If I connect everything back to stock and still run into the problem I think I’m stuck with taking it to the dealer as at this point idk what to check next.

 

[tdonoughue]

I think it most likely you have a wire switched or something there. I would disconnect and trace everything. I know mine and several others the color coding on the wires cannot be trusted. And there are many instances of odd behavior that have been resolved by figuring out that one little wire had been accidentally moved to the wrong pole. My bet is that when swapping wires around one got switched and is causing havoc.