"White Wire" Power failure

[Nayna32]

Thanks Moonlighter. That makes sense. I was wondering why they did this, and was having a dull brain moment. Unfortuantely, this adds another check to my disappointing installation.

It's the same reason I moved my electronics off the start battery years ago after purchasing my boat. Looks like I will be correcting this in the very near future.

[Moonlighter]

It still works like it is suppost to. When the battery switch is on; power is supplied to the starter, which powers the WW, PTT relays, and I'm sure other components, regardless of ignition switch position.

The wire would have been connected to the other end of the starter wire at the battery switch which would perform the same function. They saved time and aggravation by simplifying the wire routing.

Yes it works.

No, it is NOT the recommended method from Suzuki. The ECU is sensitive to voltage and the risk is that the starter will expose it to voltage drop.

[Nayna32]

It still works like it is suppost to. When the battery switch is on; power is supplied to the starter, which powers the WW, PTT relays, and I'm sure other components, regardless of ignition switch position.

The wire would have been connected to the other end of the starter wire at the battery switch which would perform the same function. They saved time and aggravation by simplifying the wire routing.

[tnadeau]

WW connected to starter + instead of Battery

If the WW is connected to the starter + post then your remote trim switch on the outboard doesn't work with the ignition switch in the “off” position, correct?

[Nayna32]

Great post!!! I'm glad I know what the white wire is for now, and what symptoms its failure can create!

I was inspecting the installation of my DF140a. I found a fused white wire connected to the starter that was looped several times because it was several feet long and tie strapped together; then went to a single bullet connector in the engine harness. It looked out of place. While moving the wire around to trace it, the wires strands came out of the blue automotive crimp connector.

I couldn't find a fused white wire coming off of the starter in the wiring diagrams. I knew it was there for some important reason, so I shortened the wire several feet, solder the bullet on and heat shrinked the end. I was going to post asking if anyone knew what it was for.

Now I know why the wire was that long, so it could be connected to the battery switch. They ran it off the starters power terminal and used the connection in the motors harness to power the ECM and other sensors. So I figured out the white wire can connect to the console harness or engine harness; probably whichever is closer to the battery switch. Glad I fixed it before it fell out on it's own. I possibly could have had a break down on open water, and had no clue why.

Thanks for the post!

[boats.net]

Thanks to Artdf175 for this post
subj: "White Wire" electrical issues -power source to the ECM

When you turn the ignition switch and nothing happens. (Battery fully charged)

This is one issue that surfaces on a regular basis and this generally deals with a loss of power source to the "engine control unit" (ECU).
With NO power to the ECM, the engine either stops (if running at the time) or will not start.
This situation usually effects the trim switch on the remote, which also fails to function.


Some background:
Generally, the battery switch (Perko type) has a short pig-tail with a connection to a "white wire" (WW). This WW feeds the power to the ignition and remote control trim switches. In some wiring configurations it can also be the power feed to the dash that powers up the boats other electronics. Note - this WW also has an inline 15A fuse. The WW can be connected directly to the positive battery terminal. Have found it can be tied into the main power lead to the engine, on the starter motor. (not recommended as this configuration can cause electrical spikes to the ECM.)
The WW splits pre-ignition switch and powers the ECM relay coil.
From the ignition switch "ON" position, the gray wire feeds back to the ECM -and is the power source for the ECM.

First let's look at the trim switch.
You hit the remote trim switch to trim the engine up/down and nothing is working. The wiring to the trim switch relay is independent of the ignition wiring but shares the same WW power feed. This allows you to raise and lower the engine without turning on the ignition. When it doesn't work- the cause will usually be related to a power failure with the WW. It can be the switch, but that seems to be rare. The trim switch on side of the engine operates independently from a different power source.

Next: turn the ignition to start/run - no response.
The ignition switch does several things- in the 'ON' position it is the primary power source to the ECM. At this point, for 4 cycle engines, a relay turns on the high pressure fuel pump. You should hear this pump. Obviously when the key is turned to 'START'- the starter relay engages and through the engines main power source, the starter motor starts the engine. One step before the starter kicks in, the 'neutral' switch must be adjusted correctly, so as to prevent the engine from starting if it is in gear. However, any interruption in power to the WW- none of this happens.
.
So what has gone wrong when these two situations happen? Usually - a lack of continuity of power in the WW or a ground wire failure.

Most common Reasons:
1) Spliced connections that have gone bad. Connectors not waterproofed that allow for unseen corrosion.
2) Wiring connectors have separated
3) Ground wire fails.
4) blown fuse

If you have power to one and not the other:
5) Ignition switch that has become defective or broken
6) If you have power to the ECM and starter fails to kick in, one of several more reasons can relate to the neutral switch.

Intermittent power loss can be difficult to find.. In my case, the wire connector to the WW off the battery switch started to fail. I would be running along, hit a wave and the engine would die. Or come up to a dock and put it in idle .. just dies and not start. Again, in my case, the WW is the power source to the dash and other electronics. The depth finder would flicker off, sometimes come back on, but mostly have to restart it. Then one day in my driveway, nothing worked - period. Started pulling wires to track and identify each one and what did they operate. Pulling on a short red wire off the back of the battery switch - the wire connector separated.. This was the power feed to the WW. Internally inside the wire connector -the wire ends were totally corroded at this point. Fixed the problem and was back in business.

- update Nov 2017-
thanks to Catislaguy there is updated info for some smaller HP models
He has a 2009 DF115HP
The primary WW off the battery to the key switch is the same but that is also where it stops.
The ECM in this smaller HP engine is powered of the Hot wire on the starter motor. Connects to the same terminal where the primary battery cable terminates.
The 'on' and 'start' position of the Key Switch - power goes to the Gray wire. The Gray wire then proceeds to power just about everything on the engine, but the ECM.
So if you turn the Key Switch -on- and nothing happens -- still need to start with #1 - fuse box; then #2 the WW; #3 the key switch itself; #4 is the Gray wire hot? if so the engine should run. If not - go back to #1 and start over.
This person, from a separate fuse panel, wired around the WW and everything worked -but why?
Answer was the ECM power source is different.
Art





Hope this little summary will be helpful..