Multifunction Guage

[zenoahphobic]

My multifunction guage that contains the rev meter, oil level meter and trim guage (no buttons) is “fading away”. Australian model 6G5 175 DETO. You won’t find that number in USA catalogs but it is the Saltwater Twostroke 175hp V6 year 2000.

At first at turn on it appeared the meter showed nothing and displayed nothing when running.
Start a pursuit of all the electrical connections through the entire boat and engine, all seem extremely clean and treated to some WD40. Nothing found.
Then I moved the boat on trailer up the driveway and completely trimmed in the engine (never used this way though).
I then noticed rev on 1 and arrow to green oil (oil was full). Then I progressed the trim button to up and gradually the trim guage read as it should, but as out or up was progressed the guage gradually dimmed away!
There was a link between trimming up and the entire display disappearing.
One concludes that the guage all functions actually worked, but trimming up is depriving “power” to the entire multi guage.
So it appears there is a dirty or resistive wire or connection somewhere, the load (current demand) increasing as the trim is trimming up.

All very well but why?

I don’t have a service manual, so to start with I need to know which wires supply the guage with 12v.There is no red wire to it.

Strange problem where I would think the trim input, or the other inputs should have little affect on the guage as it is a liquid crystal digital display.

Any thoughts?

[boscoe99]

The yellow wire provides key on voltage. Black of course is the ground.

www.gaugesaver.com if needed.

[99yam40]

the Power T&T pulls a good load sucking down the voltage some. make sure the battery is good and not failing,'
also I would clean all battery cables and connections on both the pos and neg to make sure they are not causing a bad connection dropping the voltage to the gauge

[zenoahphobic]

Thanks Boscoe, I chased that yellow and the corresponding black: both provided good voltage. And there was some resistance across the disconnected wires across the guage which seems to suggest the guage not faulty due to open circuit.

My battery charger enters the + and - near where these guages are under the dash. The pressing of the T/T had negligible drop in the supply voltage at the guage, and thanks Yam99 the fading remained after these switches were released, so voltage drop from the T/T motor appears has no effect.

And when I disconnected the yellow from supply the guage still showed the same behaviour! So some power is being supplied by either the trim sender (variable resistor), the three oil level switches, or via the tachometer signal. All of which seem unlikely unless this is via some “capacitive” means, I thought all three are powered via the meter.

I may be wrong but I am now chasing that source.

But I think, as the guage has power to it, that it has failed in some way. Strange that it still displays, then fades as trim up is increased. Anyone heard of this.

[99yam40]

sounds like the farther you trim up the motor the fading increases.
does rimming back down make the fading go away?

[zenoahphobic]

sounds like the farther you trim up the motor the fading increases.
does rimming back down make the fading go away?

Yes, as if the trim button controls the brightness of the screen.

The trim bars come up from the bottom and when they appear the screen starts to dim and completely disappear when there are about four bars (which happen to be about the setting I normally drive at - but I can’t see that having in relevance).

I have used up all the drinking stock that was in my boat fridge trying to solve this. Maybe I’ll stock it with cans of Wild Turkey 101 might help!

[99yam40]

well you did not answer my question if lowering the motor allows the screen to come back where you can see it.

and do you really have cans of Wild turkey down there?
never heard of that before.
maybe the bottles are too breakable to ship, or to heavy and costly to ship

[boscoe99]

The gauge dimming is indicative of a voltage drop problem. Measure the voltage on the yellow wire with the key on. Should be more or less battery voltage. Continue to measure voltage on the yellow wire when the trim button is pressure. I bet that you will see a considerable voltage drop.

[zenoahphobic]

well you did not answer my question if lowering the motor allows the screen to come back where you can see it.

and do you really have cans of Wild turkey down there?
never heard of that before.
maybe the bottles are too breakable to ship, or to heavy and costly to ship

Sorry must be a communication difficulty, I said yes to your question. That is the screen comes back when I trim in again; trim up slowly it dims, trim down it gradually comes back.

We have all American bourbons in bottles up to 2litres, least those that are worth drinking. Jim Bean, Johnny Walker, Wild Turkey etc. The cans I buy are those premixed with Cola, hence canned to keep fizz. Might go with the Pommy stuff if Wild Turkey doesn’t do the trick!!, We also produce some of our own whiskey but is not featured at our usual liquor outlets.

[99yam40]

OK that makes sense being a mixed drink.

As Boscoe mentioned, have you monitored the voltage at the gauge as you tilt up and down to make sure it is staying the same?

I am thinking that the movement of the cables at the motor as it tilts may be causing a connection problem.
might even be an internal problem with a wire.
It would help the troubleshooting if you could swap out the gauge to see if the problem goes away or put your gauge on a different boat/set up to see it still does it there.
if the voltage is staying exactly the same, then there could be a problem with the gauge itself

[zenoahphobic]

OK that makes sense being a mixed drink.

As Boscoe mentioned, have you monitored the voltage at the gauge as you tilt up and down to make sure it is staying the same?

I am thinking that the movement of the cables at the motor as it tilts may be causing a connection problem.
might even be an internal problem with a wire.
It would help the troubleshooting if you could swap out the gauge to see if the problem goes away or put your gauge on a different boat/set up to see it still does it there.
if the voltage is staying exactly the same, then there could be a problem with the gauge itself

Yes you make perfect sense, it would be easy to just swap guages in this case to rule in/out the guage.

You know the difficulty in just relying on voltage readings without also checking under load or knowing the current.
There is also difficulty in tapping into the wiring as even the bullet connectors have tight soft clear plastic boots, and the difficulty of working alone, operating ignition switch whilst in the cabin behind the dashboard and seeing the guage and voltmeter all at the same time.

Your day corresponds with my night and vis versa, I decided to go for a motorcycle ride in the beautiful weather.

My plan is to completely power up the guage from a good solid 12v supply. It will either brighten up, highlighting cable/ connection problem. Or if not, there is an internal problem inside the guage, that is to do with a failure with the liquid crystal itself as the guage seems to be performing its function of interpreting the sensors input correctly at this stage.

Inherently the design of the outboard wiring invites problems. As you know the 12v first goes from the battery to the engine via the starter cables, and then from the motor via the ten pin plug wire loom to the helm, and thus subjected to exposure, heat and movement.

As I have thick 32mm cable from my batteries to the electric winch via the helm, it would make good sense to tap into it at the helm and supply this ten pin cable directly from there. Or at least have this connected directly to the plus and minus bus bars. The nightmare wiring has survived faultlessly for the last twenty years. I am not the original owner but have added various things “parallel “, leaving the original virtually untouched. l need another page to describe it, but I suspect the situation with copious wiring is ommonplace.

In a few hours (when day breaks) I’ll determine whether the guage is good or bad and advise further.

[99yam40]

disconnecting the gauge and running a different 12V + & Neg directly to the gauge would be a good test

[zenoahphobic]

The plot thickens.
I did all the tests suggested. Trim current dropping voltage at the guage is only about half a volt but goes down slowly as you continue pressing (after battery tender connection removed voltage settled to 13.1; with trim on 12.6 down to 12.3. Conclusion: not an issue from the use of the T/T motor.

In keeping sweet with the wife, I squeezed the back of the boat pretty tightly against the house, so that she could also park her 4wd within our property boundary. This meant I cannot lift the motor too far.
But I discovered that trimming it further to say up 30degrees, the guage display, after going dim, then begins to increase the display brightness fully!, Trim back down the display begins to fade again till nothing can be seen, and then reaches trimmed in where the display slowly reappears!,
That is: fully trimmed in there is bright display, with arrow on full oil and rev at 1, the trim bars start to appear then all gradually fades away (as described before): continue raising engine the display slowly comes back, but no trim bars and now arrow on temp, oil on red with 8 above it. When you first turn on there is a blink where this digit flashes as an E then settles to 8.

When a separate supply is attached to the guage the above is brightly displayed. That seems reasonable it can’t read the sensors (don’t share negative) so it defaults to overheat and no oil. Conclusion: the guage works with the display working also.

This no leads to the tedious task of examining each sensor, starting with the trim sensor and wiring. Once I can have enough space to fully trim (tilt up) I am sure I can replicate that strange behaviour by just moving the trim sensor arm and follow that wiring from there. But I am very reluctant to puncture or strip and lay bare any wires.

[TownsendsFJR1300]

Sounds like your issue is right in the harness, where it does all the bending/movement, in the transom area...

You can likely manipulate, by hand, each wire in that area till it acts up (monitoring the gauge).


.

[zenoahphobic]

Sounds like your issue is right in the harness, where it does all the bending/movement, in the transom area...

You can likely manipulate, by hand, each wire in that area till it acts up (monitoring the gauge).


.

Agree
The strange thing is this does not appear as an intermittent fault as on and off; but rather the guage brightness smoothly transitions gradually from bright to dim and back again in the one trim stroke Like a household light dimmer screwed slowly clockwise then slowly anticlockwise again.