2005 4 Stroke Wiring Plugs

[ThomasGrubb]

Hello,

I have just purchased a new boat which has a 2005 150hp Yamaha 4 Stroke on the back. I found 2 plugs under the engine cowling not being used, I have attached a photo of each plug showing the wire colours. Hoping someone can assist where to plug these into, or if they are needed?

1 - the plug is a 4 pin, only 3 pins are being used. Pink/White, Pink/Black & Blue/White. These wires come from the outboard wiring harness.

2 - the plug is a 4 pin, only 2 being used. Green/Red & Green/Black. This cable runs from the multi-function gauge & I think this is does Temp & Oil. But where on the engine should these be connected?

I have seen these colour wires plugged together on some models & this could possible be my answer, but just want to confirm.

Thanks
Tom

[fairdeal]

Boscoe will clear this right up....

I believe those two should be connected
in order for your low oil pressure/high temp indicators on the tach face to work.

But I am puzzled that you say this is a "2005"
Does the model # on the bracket label end in "D"?
what is the manufacture date on the other bracket label?

[boscoe99]

You have to get up early in the morning to get a jump on fairdeal.

Don't worry if some wires are not used as compared to what the diagram below shows. Just the way that it is.


The connectors are all gendered such that when connected they will all be connected appropriately.

[ThomasGrubb]

Thanks Fairdeal & Boscoe,

So I should just connect the 2 together, and whats used is used and whats not don't worry about it?

The year model of the motor is a bit of an issue, there is no name plate on the bracket or label under the cowling. I purchased it knowing that the year model was pre 2006 as it doesn't have the blue/white connection for the sounder interface. Had it to a few mechanics here in Australia & they are saying its a 2004/2005 model based on the orientation of things under the cowling.

[fairdeal]

ahh. On your engine, to get full capability of your multifunction tach,
you need, as Boscoe has shown above, an 8-wire, 2-connector-at-each-end "trim and warning harness"
between the tach and the engine harness.

One 4-position plug is for trim - I assume that is connected and working?

the other 4-position plug - the one you don't have connected -
is needed to illuminate the "low oil pressure" warning lamp
and the "high temperature" warning lamp.
So you'll want that.

The pink/white turns on the low oil pressure lamp.
The pink/black turns on the overheat warning lamp.

What - if anything - the blue/white wire does - I don't know.
(much less, why Yamaha chose to change the wire colors,
every time they met at a connector)

(Beginning with the "2005" Model year for - USA motors -
Yamaha consolidated those three functions into a single plug on the engine harness.
That's why I was puzzled that you said this was a "2005")

[ThomasGrubb]

Ok, gotch ya. Yes the 4 wires from my gauge goes through connector 1 behind the dash & turns into a 2 wires harness - the 2 green wires which are now not connected under the cowling. Connector 2 has pink, black & grey wires which do connect up to my trim & wires colours match.

Ill connect the 2 disconnected connectors when I am home, ill probably ground each of these green cores to see that the oil and temp lights come on at the gauge.

It could well be a 2004 model if Yamaha did consolidate these functions into a single plug.

[boscoe99]

This may be the way that your motor is wired to the tachometer if the tachometer has but one four pin nylon connector. Other tachometers have two.

[boscoe99]

ahh. On your engine, to get full capability of your multifunction tach,
you need, as Boscoe has shown above, an 8-wire, 2-connector-at-each-end "trim and warning harness"
between the tach and the engine harness.

One 4-position plug is for trim - I assume that is connected and working?

the other 4-position plug - the one you don't have connected -
is needed to illuminate the "low oil pressure" warning lamp
and the "high temperature" warning lamp.
So you'll want that.

The pink/white turns on the low oil pressure lamp.
The pink/black turns on the overheat warning lamp.

What - if anything - the blue/white wire does - I don't know.
(much less, why Yamaha chose to change the wire colors,
every time they met at a connector)

(Beginning with the "2005" Model year for - USA motors -
Yamaha consolidated those three functions into a single plug on the engine harness.
That's why I was puzzled that you said this was a "2005")

Blue/white is the wire for the check engine icon or the water in fuel icon. Can't remember which and can't find my cheat sheet. For earlier tachometers. Removed in later tachometers.


US motors got the wire change in 2005. Others changed at a later date. Why???

[ThomasGrubb]

Thanks Boscoe, I do have 2 plugs coming out of the tacho - see attached photo I found on my phone.

The back connector which is hard to see is the trim harness - these wire colours match up the entire way. The front connector has 4 wires coming from the tacho (Green/White, Green/Red, Blue/White & Red/White) but then runs out to the engine with only 2 wires - Green/Red & Green White Cores which aren't connected to anything under the cowling. Ill connect this plug up with the pink/white, pink/black plug coming form the engine harness which should give me oil & temp light from what I can gather.

[boscoe99]

All you need to do is to make the connections as shown in the diagram in post #3 above. Don't worry about wires changing colours. Or wires that are missing. It drives some folks to drink. The trim/oil harness should have a tag on it indicating which end is for the tachometer and which end is for the motor.

If you have a two connector tachometer it could very well have a check engine icon and a water in fuel icon. Look at it when power is first applied. You should see all of the liquid crystals illuminate.

Most folks are only interested in low oil pressure, over temperature, and trim. And RPM of course.

[ThomasGrubb]

Yes being an electrician myself the colour thing is whats doing my head in... haha.

Thanks heaps for the information Boscoe.