Trim sensor wiring problem?

[Wave34]

2004 Volvo Penta 5.7 Duoprop.

My trim indicator started to work intermittently, and now is showing UP all the time.

I disconnected the sensor behind the engine, and I measure somewhere between 10-200 ohms when the sensor was rotated, so the sensor is working.

I used a potentiometer connected to the wiring harness to simulate the sensor, just to make sure, and the gauge is not moving.

The black wire in the plug has continuity to ground.
The brown/white wire, has no continuity to the plug behind the gauge. (I tested all the pins)

Is it possible this wire is cut somewhere inside the hull? The wire goes inside a wire loom behind the engine, so tracing it is impossible without major surgery.

There is no brown/white wire in the gauge connector, only a brown one.

 

[alldodge]

What I'm seeing is there should be a Brn/Wht go clear up to the gauge

 

[Wave34]

Thanks alldodge for the wiring.
I remember I saw some plugs behind the dash. May be the wire color changes in there.
I will check.

 

[Grub54891]

Run a temporary wire from the harness up to the guage. See if it works. Easy test.

 

[Wave34]

Problem solved.

In case this may be useful for others with similar problem.

The electric diagram shows the signal being a BN/WH wire. This is true at the sensor end. But at the gauge side, it is a PU/WH wire. (purple/white stripe), don't mix it with the PU which is 12V.

The signal wire does change color at one point. There is a plug lower behind the dash, but it is PU/WH on both sides.
The only place I can see it change color is at the big plug behind the engine.

The test I did was like Grub suggested, I cut the PU/WH wire at the gauge and ran a wire to the sensor, and the gauge started working.

Maybe the problem is in the big plug behind the engine, but since access is not easy, I decided to run another wire from the sensor plug to the gauge.

I re adjusted the sensor and now it it working.