I have a one year old 150 four stroke with a mercmonitor level one gauge. I'm looking at hooking it to a simple NMEA 2000 network to show the available engine data. The gauge has a "external power" harness and a fuse hanging off of the back that isn't connected to anything. I'm providing power to the NMEA via the standard power "T". I've read a bunch of stuff but am still uncertain what exactly this gauge harness is used for. Anyone know the right answer? Thanks in advance.
It can be used to supply power to the NMEA 2000 network, you could use that or a standard power node but do not use both.
When I installed my Mercmonitor, it was an addition to the N2K network that I had established a few seasons prior, which was using the standard power connected to the drop side of a T. So when I added the Mercmonitor, I chose to use the N2K power cable in the Mercmonitor harness, eliminating the original power drop, made for a slightly cleaner network and I was able to re-purpose the T elsewhere.
2011 Tracker PT 175 TF
2011 Merc 60 ELPT 4S
Thanks for the info. So if I understand correctly, if you hook this harness to a power source and then connect the mercmonitor to your NMEA network via the gauge's NMEA harness, the network draws power from this and no need for the standard NMEA power "T"?
Correct...
However, it sounds like you already have a working N2K network and I am not advocating you put any effort into changing it (aint broke dont fix it?). In my case when I added the Mercmonitor I was making other changes to the network as well. At that time there was some benefit to me by powering it via the Mercmonitor harness. I will also reiterate, the main thing is one or the other do not use both.
Last edited by R2Tracker; 02-26-2020 at 11:09 AM.
2011 Tracker PT 175 TF
2011 Merc 60 ELPT 4S
Ground wire should be connected to a good ground- power wire would be optional in this case, since your network is already powered.
IF you connect the red wire to a SWITCHED power source (ie: same switch that powers your graphs, or an accessory switch): REMOVE THE FUSE so that you don't end up with cross-feeds in the power circuit(s).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Are you referring the ground wire that's part of the external power adapter line or a separate ground wire? Thanks a bunch.
Last edited by stayafloat; 02-27-2020 at 12:16 PM.
The black wire that is part of the External Power Harness (acts as a redundant ground).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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