What is the sensor around the negative battery cable and is it necessary? I am relocating my battery to the back of the truck and wondering if I need to run the connector all the way back or not.

 

Yes you would want to keep that. These trucks vary the battery voltage literally all the time, it's never just charging at exactly 14 volts so it needs to know the current the charging system is at 100% of the time.

The sensor itself is called a battery current sensor.

 

Thanks. I figured it had something to do with voltage regulation but had no idea what.

Do you know if there is any reason why you can or cannot run small gauge wires next to large gauge wires?I know there can be interference with speaker wires being next to larger wires but can I run the sensor wires next to the 4 Gage alternator wire?

 

Crosstalk, emi interference. Those come to mind.

Same reason you shouldn't run speaker wire with the 4 gauge amp power cable.

 

One doesn't have to keep that, unplugging it lets the alternator run at full capacity all the time. Some folks like that, it's also a cure for flickering lights. Nice to have though and seems to help battery life. To each his own.

 

You sure about that?

Unplugging the GBCM causes the truck to charge to 13.8v which is lower than if it was hooked up and working.

You also have to make sure every ground cable from the battery negative post goes through that sensor. If not, your truck will charge very high like 15v+

 

Nobody that's disconnected it mentioned over-charging the battery. Folks have been turning that thing off since 2006 or so.

 

It charges low when disconnected, not high. Typically 13.6-13.8 vs the 14+ you should have with it connected

 

That's right, it is constant and doesn't change like the old way.

 

On my 2006 I was charging around 15V and noticed this because some switchback LED's I installed would start flickering like strobe lights with the engine running, but were fine while it was off. I thought maybe my alternator had gone nuts so I replaced it. Now it charges *slightly* lower but still seems a bit high; I'll have to go back out and hit it with the meter to see what it's doing these days. I'm running regular LED's for signals since the switchback install failed based on that high charge rate.

For what it's worth my harness is dead stock with that sucker in place, and I did just replace my negative cable with a GM piece routed back through the way the original was. Old cable had some corrosion wicking down it which I think may have been screwing with the charge rate..

Richard