2003 Mercury 2.5l 200hp EFI Motor connections??

**Coxwain** · 10-01-2018, 09:04 PM

I have a few wires/connectors that are not connected. What are they for and should I be using the connections?

OT749297

2003 Mercury 2.5l EFI 200HP

Not easy to upload photos, please click link for pictures.

https://photos.app.goo.gl/NLZRzMGTF6k4XXyS7
I have added photos

**Coxwain** · 10-02-2018, 10:03 PM

**Matt Wayne** · 10-03-2018, 07:59 AM

The 2 big plugs are for smartcraft. One is for the blue data cable and the other one is for the fuel/paddle harness. So unless you add a smartcraft gauge you want use those. You want use the purple wire and I can't really see what that other one is.

**Coxwain** · 10-03-2018, 08:14 AM

The fist picture has a Red/purple wire which is connected and a black or dark purple with no connection.
2nd picture is purple no connection
3rd and 4th are connection terminals
i only understood that there is one connection terminal for the smart craft setup. and that I only needed this one cable to go to a junction box from the motor

<MODERATOR EDIT- PLEASE SEE ANNOUNCEMENTS REGARDING LINKS>

**Coxwain** · 10-03-2018, 08:32 AM

Thank you for your e-mail regarding your Mercury outboard engine. We appreciate the opportunity to respond.
Your engine has the ability to interface with a NMEA 2000 compatible device via a Smartcraft Gateway device. If your display is NMEA 2000 compatible, and is on a NMEA network, please see diagram below for necessary components. These items can be ordered through any Mercury Marine dealership.

**Matt Wayne** · 10-03-2018, 08:55 AM

That's correct. You only need the blue data cable for the gauge to work and read off the engine. However if you wanted to read your fuel tank and oil tank levels with the smartcraft gauge you have to install the fuel/oil harness and it connects to the smaller plug. You don't have to use this but it's an option.

**Coxwain** · 10-03-2018, 09:09 AM

well I do want to use that. lol.

that seems to be a different harness?

**Coxwain** · 10-03-2018, 09:10 AM

Also, can I use this guage?

**Matt Wayne** · 10-03-2018, 09:16 AM

Yes the fuel/oil harness is a different harness. 859743T04 is the harness you need for your engine. 2006 and later is different.
Yes you can use that gauge.
If you do use the smartcraft to read your fuel tank level your analogue gauge you have now will not work. You can only use one or the other but not both. You can however add a small system link fuel gauge to replace your old analogue fuel gauge and it reads off the smartcraft monitor. Hope this helps

**Coxwain** · 10-03-2018, 09:51 AM

thank you, it does help.

What am I to do with all the wire connections at the back of those gauges? lol

**Matt Wayne** · 10-03-2018, 11:59 AM

You can follow the wires back and see if they are plugged into the harness and remove the plug or just tape them off.

**EuropeanAM** · 10-03-2018, 06:10 PM

You are missing a portion of the wiring harness for the engine- without it, you will not be able to connect a 6 pin fuel/oil harness.

Please take a moment to review the Forum Announcements- we don't support auction/bay/zon purchases here.

Let's start by deciding which Smartcraft System you would want to use. Then we can specify the simplest-possible method of installing.

**Coxwain** · 10-03-2018, 09:29 PM

i initially thought it would be good to use my lowrance elite ti nmea2000 connection for guages.

then I see the mecruy gauge listed above and since my speedo isnt working, i could put it there.

Also, fule gauge just died today. Not sure if that is a fuse ?

**EuropeanAM** · 10-04-2018, 08:11 AM

Unknown on the fuel gauge- you would simply need to test the power, ground, and sender circuits to determine what is causing the problem.

You've got a PM.

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2003 Mercury 2.5l 200hp EFI Motor connections??