2006 F115 wiring

Hello,
This is going to be a little long, please be patient.
Boat is a Maritime 20p with a 2006 4stroke 115tlr. Dealer prepped in 05.

My issue started with my speed gauge stuck at 28mph. Then my temp gauge on my Lowrance 332c stuck at 123 degrees. (transducer with temp)
While i was looking at the speed and tach gauges I noticed on the tach the blk, pnk org and gry wires were hooked up to the tach gauge...along with the other engine data wires.
However when i looked at the engine the 4 wires were not hooked up to anything. All I get on the tack is trim, and engine hours. The ones not hooked up are for oil and temp warnings i assume?? There is no place to hook them up. why would they not be hooked up?

Part 2
I ordered the service manual for part 1:-)
After looking at the gauges I started to think... should I just go all Lowrance net nmea2000 for gauges instead of the Yamaha tach and speed gauges?? has anyone done this before and is there an easy harness that I can plug in to get engine data?
Thanks
T

[boats.net]

The speedometer tubing is probably pinched or kinked somewhere. If they used the older Trim/Oil harness it would have two 4 prong connectors on each end, the 2006 engine only has 1 connector. If the trim gauge works then the oil and overheat indicators will work. The Lowrance could be a bad temp sender or a problem in the Lowrance.

Would the speed wheel on the transom be connected to the speed tach or is there some other speed indicator on the motor it's self? It seems that the speed wheel cable plugs into the Lowrance unit.

[boats.net]

The speed wheel on transducer is for the Lowrance. The Yamaha speedometer gets it's speed signal from outboard lower unit by way a pickup tube on front of gearcase housing(a very small hole in housing). The rubber tubing between gearcase and speedo may be kinked.

Thanks for all the help everyone. In regards to the wiring; There are 2- 4 pin connectors. One of the connectors is plugged in and the other is not.
It seems nearly impossible to get manufacturing date of the outboard, but my warranty has a date sold of 11/01/05. They call this a 2006 model.
For the NMEA question - I can't find any info on NMEA compatability for this engine. There is limited information on Yamaha command link...

**My end goal is to have more information. I want engine temp, water pressure, oil level...etc
All I have now is RPM, TRIM, gas level, and Speed. Correct me if I am wrong but shouldn't oil level and temp information show up on one of the yamaha gauges?
Is this a matter of an adapter to allow me to connect the other 4 pin set?

Thanks
T

[boats.net]

The gauges you have will show a warning light for overheat and low oil pressure even though one of the connectors is not connected to anything if your dealer installed gauges correctly. You can add a Temp gauge to get engine temp readings. That engine does not have the capabilty for a oil pressre gauge just low oil pressure light. The multifunction speedometer will not connect to GPS(NMEA 183 output) for speed signal but the Command Link gauges will. The Command link will display engine temp and water pressure with optional sensors.

Thanks for all the help. If I can return help with any computer security questions feel free to fire away.

Thanks
T