Merc to Lowrance to gauge

[Paintworx]

I have this posted in the Lowrance forum and not quite figuring things out.




I just had a new Pro XS rigged up on my Ranger and the shop did not have the Junction box that is apparently required to run engine data to my Carbon. I have been using the smart craft gauge but I finally got the Mercury 4 port Junction box that they say I need to have In order to get data to both units.

Using one of the harnesses that came with the engine I plugged the gauge plug from the main harness into the J box and then ran the system link to the Control box with the round connector (I think this is the NEMA box) that they had previously installed. I ran the plug marked gauge back up to the smart craft.

I now have data at the HDS but not at the SC Gauge. It seems like the only way I can get the SC gauge to work is plug direct to main harness. When going through the Jbox it does not get info.

There is a part of the harness I am using to link everything that is marked System Link and another Marked V link and some wires (purple, peach/blue, Ground. And a 3 pin plug. Not sure if these are needed but not wanting to start tying into power.... this seems like it should be pretty simple stuff but I’m stumped.

The ports on the 4 port box are not marked but wondering if the connectors need to go in a specific port?


engine model 12500033A
Serial 3B 040659
250LPXS

[EuropeanAM]

You're confusing systems here.

One system: SMARTCRAFT (10-pin plugs, one from harness to j-box, then one from every SMARTCRAFT device into the J-box).

System Link gauges do not go to control, NOR does the Smartcraft wiring (on your mechanical control 250 ProXS).

System LINK gauges connect from the system link plug on the MASTER or PRIMARY Smartcraft Device, and then daisy chain from one System Link gauge to the next.

Suggest getting a few pictures of what you have, and also identifying the source of the components you have.

[Paintworx]

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[Paintworx]

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[Paintworx]

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[Paintworx]

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[Paintworx]

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[Paintworx]

Sorry about all the separate posts. It would not seem to let me add multiple pix. Somehow I managed on the last post by mistake.

[EuropeanAM]

...and also identifying the source of the components you have.

Where did these items come from?

[Paintworx]

I bought the 4 port J box because my dealer told me that Merc told them I needed it. The VesselView was installed by the dealer.

The harnesses came with the Pro XS I believe. The dealer gave them to me after the engine rigging.

[Paintworx]

They are all Merc parts if that is what you are asking.

[EuropeanAM]

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The J-box and the harness pictured above must be installed, otherwise the Vessel View would not be functioning (unless you have two of everything).

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This harness is used to connect the System Monitor (that's in your dash) to the J-Box. The two 10-pin connectors are marked JUNCTION BOX and GAUGE end.

The System Link plug is used to connect to the FIRST System Link Gauge. You then simply daisy-chain from one to the next to the next across the dash.

Note: System Link gauges should plug into the MASTER instrument (which in this case may actually be the Vessel View). If the System MONITOR had been installed with a previous engine, or in another boat/engine combo, it MAY need to have a Master-Reset performed so that it can latch the system as a Slave Instrument (or Station-2 more than likely).

[Paintworx]

Thanks for taking the time to help me out. The way you described is how I have it hooked up. The Lowrance works fine but still no gauge. The only way I can get the gauge to work is to hook the main harness 10pin direct to it. If I go into the Jbox and out to the gauge it does not work. The parts/engine are all new and not previously installed.

[EuropeanAM]

I'm going to take a stab in the dark and guess that you have neglected to connect the lone BLACK wire on the harness you're supposed to use for the System Monitor to a good ground.

Without that- the gauge will not function at all. And the harness MUST be installed with the correct end at the J-box.

[Paintworx]

Ya. The single wires are not connected to anything. There are 3 if I remember right. One is the black one and a purple and a pink. Also a couple 3 pin plugs in the mix.

[Paintworx]

Update. Just went out to the shed and hooked the ground wire up to the buss bar that was literally 3” away from where those 3 wires were zip tied out of the way. And what do you know. The gauge works. DUH. I feel like a real dummy. I was convinced those extra wires were for something else and the gauge got power/Ground through the 10 pin connector since it worked when plugging direct to harness. Apparently grounding does not pass through the 4 port J box.

I REALLY APPRECIATE YOUR HELP DON !

you really held my hand through what was something so EZ. God I’m a dummy.

Thanks again.

[EuropeanAM]

Just for future reference: The J-box does indeed have a ground that passes through it. Just so happens that the System Tach Harness (which is what is used for the System Monitor, such as you have) does NOT have the ground wire in the J-box end plug. Must be grounded separately (by design).

Glad it was simple.

[Paintworx]

Thanks for explaining.