F115 Trim sender / gauge - strange problem...

[yam_sweden]

Hi, I have a Yamaha F115 -07 with round digital multifuntion tachometer (6Y5?).
Trim level reading is wrong, it shows max trim when it should show approx half trim.
I have calibrated the cam at the transom, starting at 2 bars,
so we can say it moves to fast over the scale...

The trim sender was replaced - no change...
The gauge was replaced - no change...

I have verified it is a 2 wire sender and that gauge DIP-switches is set accordingly.

Marine shop think it is strange and does not seem understand...

I built a "lab" at home with old gauge and potetiometer simulating sender
and measured resistance and cheched corresponding gauge trim levels.

Went to the boat and disconneted pink wire from gauge and measured resistance
between pink at engine side and black with battery disconnected, at different trim levels;
all seemed okey...confused...

Connected everything and powered up and measured voltage on pink when trimming;
now I detected difference from lab ! -Voltage not the same at all trim-levels.
Disconnected pink and measured voltage on engine side while trimming,
I was surprised to see that there was voltage that varied with trim level.

Pink from sender does not seem to go straight go gauge but engine is involved in some way
and sending voltage ?

Sure I could have got something wrong but this is what I have...
This have been for years now and I have spent a lot of time and money...
Anyone knows whats going on ?

/Tobias, Sweden

[yam_sweden]

I have been reading on forums...found single pink wire connected to single pink wire, disconnected them and now it seems to work :-)
It enables NMEA / command link ?

[boscoe99]

You found your problem.

Digital gauges use the pink wires connected.

Analog gauges use the pink wires disconnected.

[yam_sweden]

Thank you.