Command Link challenge??

[jbman1945]

I am working on a 36 Contender which is my neighbors and have all electronics working except fuel gauges correct. boat has 3 yamaha 250s and a Command Link system that links into a Garmin display via nema2000 that comes from the Yamaha bus. Have info coming in from all 3 engines, rpm, temps, tach, etc...but can get no fuel tank info on any of the 3 tanks. Found two tanks access and they have yamaha type bus fuel senders, can not find third access yet. Have a bus in the stern compartment that has all 3 engines to it, and a bus out heading forward. In center ****pit have only 2 bus units with all plugs accounted for power, bus to bus; and other gauges plus ONE cable coming from stern.
Would you guys guess there's another bus buried somewhere since I see two fuel sender outputs on top of 2 tanks but they don't go fwd or aft.

On yamaha gauges I get two tanks to read? On Garmin display I get NO tanks.
Strange, am I missing something here. Don't have good access to center hull and third tank at this point and guess all three tanks must go to a hub? but if so why won't it display on garmin??
Garmin screen shows these devices...
Garmin gps17xnema2000
6P28591A21
6Y88350T00 (3 OF THESE LISTED TOGETHER)
6Y88350S00
6Y88350F00
6P28592A22(2 OF THESE LISTED TOGETHER)

Any help really appreciated...

thx..

[boats.net]

Fuel tank senders are not connected directly to Command Link network, they are connected to speedometer through the(fuel sender/GPS NMEA 0183 harness) pink and black wires(the square speedo will read two gas tanks) so you probably wont get tank level data through NMEA 2000 network.

[jbman1945]

***, thanks so much for your comments! Problem is I can't find really good info on Yamaha installations, after the fact; i.e. working on used stuff. Your comment really makes sense if they are not connected to the nema 2000 system. That really is helpful since I know there are no inputs going into garmin from the 0183 harness, so they must be going only to the yamaha gauges...and they appear to work on two tanks; but nothing shows on garmin. Any suggestions for a solution?? Maybe trying to find the third tank 0183 output and moving it directly to a separate gauge? easiest solution to get fuel level readings.

or; is there a way to get info from 0183 to Garmin, Garmin has an input for this data but nothing is hooked up to it. can you bridge, i.e. solder a "Y" on the gauges so data goes both to yamaha and garmin 0183..surely they must make some sort of connector that would do that??

Can you advise if I can hook more than one gauge by 0183 together, there must be two now, need three to read. do you simply hook them all together; then maybe to a garmin0183 input. Found new Yamaha gauges show up to 4 engines, fuel so that might work. Think I only have one wire coming from tank area to current yamaha gauge.

Couldn't find out where tank gauges were and why they didn't show up so you are really the expert...thanks much...

[jbman1945]

Problem found

Thanks to your help on the forum, you sent me in a direction where I could find the problem. Knowing that the fuel gauges will not send info via NEMA 2000, but 0183 sent me looking in another direction. By back tracking from the fuel gauge, there were two inputs that went into the harness. Un wrapped the harness and found some previous owner with talent! took one of the fuel gauge wires and ran it to the switch which would normally be a choke switch on the key panel and made it a two way switch. that switch provides a switch between tanks 2 and 3 for a reading and tank 1 is constant.

What a find and thanks for your help on the forum!!