Trim gauge hookup

brooksville_rebel

Petty Officer 1st Class
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Aug 12, 2011
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240
So now that the tachometer is good to go and its daylight out I am going to try to get the trim gauge working.
I have researched and searched it and I don't think it was ever hooked up. It has wires to it but don't think it was hooked to the sending unit.
I followed the wires according to what I have found on the net. But I haven't found any actual hookup images/videos to compare.
What I see is this setup so far.
Coming into the trim up and down button on the throttle is 3 wires. Red/pinkish/green/blue - they are old and faded so kinda hard to tell colors) ( wires to throttle.jpg and ThrottleTrimWires.jpg )

Following the wire to the engine gets a little funky (at least to me) but in the engine those wires are spliced to to 3 different colored wires (green/orange/pink) .(engine splice.jpg)
Then the continue down to another splice (2nd splice in engine.jpg) were they become the green/white and blue/white.

From that second splice the red/pinkish wire goes to the big black thingy (can't recall what its called) (wereredpink goes to.jpg and PinkRedWire.jpg)

The green/white goes to top of engine to big block of connections ( green wire landing.jpg and greenWireTop.jpg)
The blue/white is connected just below that on the block of connections were the big fat red wire other end is connected (see green wire landing.jpg).

What I have seen is a brown / white to the gauge but I have no brown/white. I have a tan but thats for the heat alarm. And a black yellow that goes into the ignition but is unplugged coming out of it so not sure were that goes as that I read was the stop engine ???
 

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  • green wire landing RE.jpg
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  • GreenWireTop RE.jpg
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  • WereRedPink Goes to RE.jpg
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  • 2nd splice in engine RE.jpg
    2nd splice in engine RE.jpg
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brooksville_rebel

Petty Officer 1st Class
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Aug 12, 2011
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240
I am confused as to if I need to run a wire and from were on the engine or do I splice into the green/white or/both blue white going to the trim button ?
 

alldodge

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40,581
Looking at your pics I think its a Mercruiser but not for sure. So first let us know what is the manufacture

Here is the wiring diagram for Merc
Trim wiring Merc 2012.jpg
 

alldodge

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Also the above are what your showing is for the trim pump.

The gauge is separate and has 12V to the gauge then has a Brown/White wire which goes to the sender on the drive and the other side of the drive goes to ground
 

GA_Boater

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Brooks has a 1987 3 cylinder 70 HP motor.

I tried to find trim sender to gauge wiring and am coming up blank. I don't know if Mercruiser and Merc OB's use the same color codes for trim gauge/sender.
 

wrench 3

Commander
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Aug 12, 2012
Messages
2,108
If the wiring to the gauge is from Mercury there will be a brown/white wire with a single connector on it breaking out of the harness just before the main plug at the engine. It should be close to where the green and blue come out. If there is no brown/white wire there, check to see what is connected to the S terminal on the gauge.
 

brooksville_rebel

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Thanks guys. I see no brown white wire in the engine or under the console. The engine is a mercury and so is the harness. Or at least thats what I was told. I am going to double check in the morning. I found a pic I took of the engine wiring. Since you all know were the wires should actually be you can tell if theres a sender wire. I can't see a brown white and don't ever recall seeing one.
Crap images too big to upload. Will resize them in the a.m Thanks for all the help
 

brooksville_rebel

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Aug 12, 2011
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Okay I put on the glasses and went through every wire on the engine and then got under the console with the glasses on and there is NO brown and white or white and brown wire on this boat. So I don't think it ever got wired up.
So assume I have to run this wire from the engine to the gauage but not sure of were I attache to on the engine. And is brown/white the only wire or do I need to run a black wire also ?
Thanks
 

brooksville_rebel

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Aug 12, 2011
Messages
240
Also the above are what your showing is for the trim pump.

The gauge is separate and has 12V to the gauge then has a Brown/White wire which goes to the sender on the drive and the other side of the drive goes to ground

Thanks tho I have no idea what the drive is or were its at or meant by it. I looked on line but either I'm using wrong terms or missing it completely.
Thanks
 

alldodge

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The item in 6-A7 to the left of the tilt lock lever is the trim sender and must be there to send the signal to the gauge.
 

GA_Boater

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If you have a trim sender, 6-A35 should have what you need to figure out. Not all motors with TnT have trim senders. Since you have a gauge, it's good bet you do unless the motor has been swapped out over the years. :noidea:
 

wrench 3

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Did you check to see what was hooked up to the "S" terminal on the back of the gauge?
If it ever had the gauge hooked up there mite still be a wire running back to the transom. There will only be one wire. The black from the sender grounds to the bracket on the engine.
 

brooksville_rebel

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No wire. I found a pic I took of the bottom of the gauges for reference and that wire was never hooked up to it.
So is the sender under the cowling or on the side of the engine bracket ? Storming here so didn't have much time to look. I saw nothing on the outside of the engine anywere near the tilt lock lever or holes for were one might have been at one time.
 

wrench 3

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Aug 12, 2012
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The sender would be on the port end of the pivot shaft that goes through the top end of the ram on the trim pump ass. There should be a slot in the end of the shaft that moves the sensor and a bolt hole on each side of the shaft hole in the bracket to mount the sensor.
 

brooksville_rebel

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Aug 12, 2011
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I found it finally. I wasn't getting the engine tilted up high enough to see it.
Next question is how is the wire routed form there to the gauge ? I did not see any wire passage holes ? Does it go up into the cowling some how or out/down the back of the engine ?
Thanks and I really appreciate the help and education.
 

alldodge

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My guess is the wires stay outside the cowling and don't mate up with the engine harness. This is the same way Merc does it with inboards. Just need the one wire coming from the gauge and ground the other side of the sender
 
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