Where should the battery sub cable connect?

[rustynutzz]

The (white wire) on a dual battery setup with a switch. Battery one, two or common on the switch?

[artdf175]

can you be a bit more definitive?
there is a white wire that has been talked about on forum that runs from battery switch to ignition/gauges..
if that is the one you refer to.. it comes off the power side of the switch
I have not taken the switch apart . but there is a hot (red) lead off the switch that my "white" wire is spliced to.
Art..

[rustynutzz]

The white wire in question is the battery sub wire that connects the ecm to the batteries.

[Harper2]

The common on the battery switch.

[Harper2]

can you be a bit more definitive?
there is a white wire that has been talked about on forum that runs from battery switch to ignition/gauges..
if that is the one you refer to.. it comes off the power side of the switch
I have not taken the switch apart . but there is a hot (red) lead off the switch that my "white" wire is spliced to.
Art..

Art, the sub battery cable is the white wire that is most often referred to on the forum. It is the one that I wrote a long thread on a couple years ago (when I was still just Harper). It goes from the battery (or in the case of a dual battery setup from the common of the battery switch) directly to the ECM relay. There is a splice in the wire that goes to the ignition switch which powers everything through the ignition switch, but that is not what has caused most problems. The fuse is between the battery and the splice, so if the fuse blows or otherwise goes bad, it will of course affect power to the ignition switch. But the "white wire" is not otherwise related to anything on the ignition switch. It's main function is solely to provide power directly from the battery to the ECM relay, so as not to be affected by any voltage drop thru the battery-to-starter cable under high-amp start conditions. The white wire could be disconnected between the splice and the ECM relay, and the engine MIGHT start, and if already running, would not shut the engine down, because there is another wire (grey, I think), from the ignition switch that powers everything, including the ECM and engine relays.

Edit....PS....the sub battery cable (white wire) is addressed on page 3-14 of the DF150/DF175 service manual.

[rustynutzz]

Art, the sub battery cable is the white wire that is most often referred to on the forum. It is the one that I wrote a long thread on a couple years ago (when I was still just Harper). It goes from the battery (or in the case of a dual battery setup from the common of the battery switch) directly to the ECM relay. There is a splice in the wire that goes to the ignition switch which powers everything through the ignition switch, but that is not what has caused most problems. The fuse is between the battery and the splice, so if the fuse blows or otherwise goes bad, it will of course affect power to the ignition switch. But the "white wire" is not otherwise related to anything on the ignition switch. It's main function is solely to provide power directly from the battery to the ECM relay, so as not to be affected by any voltage drop thru the battery-to-starter cable under high-amp start conditions. The white wire could be disconnected between the splice and the ECM relay, and the engine MIGHT start, and if already running, would not shut the engine down, because there is another wire (grey, I think), from the ignition switch that powers everything, including the ECM and engine relays.

Edit....PS....the sub battery cable (white wire) is addressed on page 3-14 of the DF150/DF175 service manual.

***, thanks for the quick response. It was a "white wire" issue. I was getting different voltages on my in dash voltmeter from my two batteries and could not figure out why. After ruling everything else out, someone from the hull truth suggested the white wire. Come to find out the white wire was installed on battery #1 positive and not the switch common so while running on battery #2 the voltage on the dash only read the battery voltage. Here is a link to the thread. Thanks again.

Help me understand my boats electrical system (problem solved, Suzuki "white wire") - The Hull Truth - Boating and Fishing Forum

[artdf175]

Mike thanks for the clarification
I guess I was looking at 3-14 drawing differently
The white fused "sub-battery cable" first goes through a harness to the ignition switch on one side of the wire harness with the other side to the white wire connecting the ECM main relay
The white that goes to ignition switch , with turning the key feeds the GRay through a connector to the B/BI wire that feeds power to the 23 terminal of the ECM
Page 4-11 is more detailed than above drawing with a slightly different color wire off the start side of ignition switch which powers the neutral switch before continuing on to the ECM
So I do have to slightly disagree in that the 15A fuse comes first in line before branching one way to igition-key-ECM / and the other side to the main relay-fuses-starter relay
So if there is a problem in the fused line before it gets to the connector - nothing works. And there is no power to the ecm if the ignition switch side
fails
And for my own personal experience - if the white off the common battery switch fails- in my case before the 15a fuse- the engine stops dead ....

The gray wire off ecm (terminal 20) goes to the switch side of the end main relay which appears to be an open circuit until activated.
Art

Rusty. It is good that you found the mistake and was able to correct it

[Harper2]

Hi Art,
I was incorrect to say that the engine would continue to run if the 15A fuse blows. If that fuse blows, the ECM relay would be deactivated and shut the ECM down. The white wire goes through the 15A fuse to the hot side of the relay coil, so even with the ignition switch off there is potential to the relay coil ALL THE TIME. The relay coil is grounded through the ECM and when the ignition switch is turned on, it completes a power circuit to the ECM via the grey wire. The ECM then grounds the ECM main relay coil, and the relay switch is thus closed. The hot side of the relay contacts goes through two 30A fuses that are connected to the hot side of the rectifier/regulator and the relay takes that power and provides the main power not only the ECM, but the fuel pump and who knows what else? Those wiring diagrams in the back of the manual are so darned small that my eyes are crossed from looking at it for so long.

These Japanese are verrrry tricky people..........