Mercury VesselView Mobile / Junction Boxes / Helm Guages

A

AK11702

New Member
Sep 7, 2022
7
Boat Info
2006 SeaRay Weekender 225, Garmin 741xs
Engines
Mercruiser 350 MPI 5.7L 300HP w/ Bravo III Drive
IMG_5249.jpg

I am looking to add a junction box to my helm in order to simultaneously run my helm smartcraft guages as well as Mercury VesselView Mobile. Currently, my 10-pin engine harness runs directly from my engine into my Tachometer (the tach has a small digital display for smartcraft data).

Can I unplug my engine harness from the Tach and plug it into SmartCraft junction box 5-way Part No. 98-8M0165557 and then use Mercury-Mercruiser 84-891957K01 CAN P Link Harness Assembly to connect the junction box to the Tachometer? Or is there another cable that is more appropriate for connecting the junction box to the tachometer? Or is there another setup entirely that is more appropriate for running both helm guages and vesselview mobile?
 
Last edited:
You should be able to do exactly that. One thing however - does the existing harness have the CAN termination resistors in it or does the gauge have the resistors? There needs to be a termination resistor for CAN H and CAN P at the J-box.
 
I don't see any CAN termination resistors anywhere in its current configuration. All new to me, but I'm assuming that I'm looking for a 10-pin connector with a yellow or red cap.
 
AK11702 said:
I don't see any CAN termination resistors anywhere in its current configuration. All new to me, but I'm assuming that I'm looking for a 10-pin connector with a yellow or red cap.
Click to expand...
Not necessarily, many OEM cable harness have the resistors integrated in them. The yellow cap for the ten pin are the resistors. There are three variants.
 
You can determine if the resistors are in the harness if you measure resistance with a DVM meter across pins J and K (CAN H) and then pins G and H (CAN P) on the disconnected ten-pin connector. If the resistors are in the harness, you should see 60 ohms at both.
As an edit - some of the harness have a two pin blue capped connector - that is also an resistor.
 
Last edited:
Thank you, this is very helpful. Do you have a link to a pin diagram that matches the pins to the letters you outline in your post (J, K, G, and H)?
 
Thanks for the diagram links ... I got to the boat this morning and was able to get a better look at the wiring. The engine harness has a sticker (see picture) that says 'Termination Resistor on This End'. Is it safe to assume that equates to your point that the resistor is integrated into the wire?
Terminatin Resist.jpg
 
AK11702 said:
Thanks for the diagram links ... I got to the boat this morning and was able to get a better look at the wiring. The engine harness has a sticker (see picture) that says 'Termination Resistor on This End'. Is it safe to assume that equates to your point that the resistor is integrated into the wire?
View attachment 133451
Click to expand...
It looks like you are good to go. Add the J-box, a patch harness for the existing gauges, and your new VV.
 
Thanks again for your help. I gave everything a go this morning but when I key on the engine the guardian alarm remains on as a constant beep and the gauges do not register the engine. I plugged the harness into the j-box, the vessel-mobile into the j-box and the patch harness to the existing gauges. If I remove the the patch harness the guardian alarm goes away. Do you think I need a different type of patch harness? The one I'm trying to use is Merc part no. 84-891957K01 (https://www.mercruiserparts.com/891957k01-harness-asy-link).
 
AK11702 said:
Thanks again for your help. I gave everything a go this morning but when I key on the engine the guardian alarm remains on as a constant beep and the gauges do not register the engine. I plugged the harness into the j-box, the vessel-mobile into the j-box and the patch harness to the existing gauges. If I remove the the patch harness the guardian alarm goes away. Do you think I need a different type of patch harness? The one I'm trying to use is Merc part no. 84-891957K01 (https://www.mercruiserparts.com/891957k01-harness-asy-link).
Click to expand...
O - I was unaware you were having alarm issues. The patch harness and J-box are simply a wired pass-through so they would not be a contributor to an alarm. Also, the issue the gauges do not power up or show any data is concerning. Give Mercury a call about the harness P/N for that application. The master gauge provides the power and data for the other gauges (Link Sys gauges) - maybe you have an issue with the master gauge.
 
The alarm only goes off when I use the junction box and patch harness. If I just plug the engine harness directly into the tach gauge, the gauges operate as expected and no alarm.
 
AK11702 said:
The alarm only goes off when I use the junction box and patch harness. If I just plug the engine harness directly into the tach gauge, the gauges operate as expected and no alarm.
Click to expand...
Roger that - so appears an issue with that particular harness. Or, unlikely but a defective J-box....
These issues with or without the Link connected?
You could remove that harness' covering and do a wire to wire association between the two connectors (pin one goes to socket 1).... to make sure nothing is crossed up.
 
J-box seems ok b/c the vesselview mobile works when plugged into it, only issue is the patch harness to the gauges. The wire association process you mention is a bit above what i'm willing to get in to. I'm going to see if I can find out more about the patch harness. I'm surprised there's not more information out there as to what cable is appropriate for this setup. I did email mercruiserparts.com prior to purchasing the j-box and patch harness from them to confirm if that was correct setup but they never got back to me. I went ahead and purchased anyway figuring it was worth a try and I couldn't find any information that would suggest that harness wouldn't work. Unfortunately, opened cables from them are not returnable.
 
I just looked up that harness P/N and it is definately the wrong harness - it is for bridging between port and starboard engine systems; not for a patch.
 
AK11702 said:
J-box seems ok b/c the vesselview mobile works when plugged into it, only issue is the patch harness to the gauges. The wire association process you mention is a bit above what i'm willing to get in to. I'm going to see if I can find out more about the patch harness. I'm surprised there's not more information out there as to what cable is appropriate for this setup. I did email mercruiserparts.com prior to purchasing the j-box and patch harness from them to confirm if that was correct setup but they never got back to me. I went ahead and purchased anyway figuring it was worth a try and I couldn't find any information that would suggest that harness wouldn't work. Unfortunately, opened cables from them are not returnable.
Click to expand...

As @ttmott suggested, a call to mercury to confirm the part number of the correct patch harness is the way to go.
 
I had the same problem. I had an old patch cable from an outboard and I shortened it. Every time I tried to connect the j-box under the helm, the gauges would not work. I then connected the j-box near the engine with the old patch cable and everything came to life.
 
You must log in or register to reply here.

Forum statistics

Threads
113,163
Messages
1,427,605
Members
61,073
Latest member
kolak3
Back
Top