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.