Trim and Tilt on 2008 Yamaha 300 HPDI

[boscoe99]

---------------------------

[99yam40]

could they be Zener diodes that bleed excess voltage to ground?(voltage spikes)

So does this diode device tie into the Sb and LG control wires or the wires to the Motor itself?

The way it is drawn seems to me the 2 diodes block current flow to ground '
only time they would allow current flow would be if they failed closed/shorted, or if they are Zeners then they would shunt excess voltage to ground.

or is my memory on the way diodes are drawn wrong?

do all Yamaha motors with T&T have these diode devices?

[Reel1Fishing]

My OX66 does the same clicking noise as OP. I usually have to press up/down button a few times and then it activates. Replaced relay as well, so going to look into that diode to see if it fixes mine and report back.

[boscoe99]

So does this diode device tie into the Sb and LG control wires or the wires to the Motor itself?

The way it is drawn seems to me the 2 diodes block current flow to ground '
only time they would allow current flow would be if they failed closed/shorted, or if they are Zeners then they would shunt excess voltage to ground.

or is my memory on the way diodes are drawn wrong?

do all Yamaha motors with T&T have these diode devices?

It is embedded within the main engine wire harness assembly. Electrically connected to both trim switches.

The diodes are normal types. Not zener diodes.

Some models have them integrated within the relay assembly. Some don't have them if my memory serves me well.

Here is a snippet from another models diagram that shows the complete circuit.
zshorel.jpg

[boscoe99]

My OX66 does the same clicking noise as OP. I usually have to press up/down button a few times and then it activates. Replaced relay as well, so going to look into that diode to see if it fixes mine and report back.

If a relay clicks and the system does not work on one model, and the problem is the diodes, then if and when the relay clicks and the system does not work on another model, then it has to be the diodes.

[boscoe99]

is my memory on the way diodes are drawn wrong?

The diagram is correct with respect to the orientation of the diodes.

[99yam40]

The diagram is correct with respect to the orientation of the diodes.

Then diodes block current flow to ground and to each other(the up and down switch circuits) which no sense to me in DC circuits.

or are they there to block some AC signal or current from back feeding,
maybe when a diode fails in the rectifier that lets some thru.
it would take 1/2 of the AC to ground

I do not think we will ever learn way the designers put them in there

[panasonic]

Here is a silly question. What would happen if someone, two people actually would be needed, pressed the trim button on the engine say..."up" and someone else pressed the trim on the helm "down" at the same time?

[99yam40]

I would think that if one relay is picked up then the other could not be operated, but I do not see how that could be prevented even with the diodes unless there is some mechanical linkage

[Txbass12]

I used the boat today and no problems at all with the trim and tilt.

[TownsendsFJR1300]

Question, (as I'm "electrically challenged").

Why bother putting a diode in that system at all?

Doesn't seem to be needed and doesn't seem to "protect anything" (and can only cause issues)?


Lastly, is this diode probably/possibly/etc used in other engines? (Just good to know).

.
.

[boscoe99]

https://www.google.com/search?q=coil...hrome&ie=UTF-8

[boscoe99]

Stolen from the innerweb. Relay for a Volvo. Embedded diode.
zreldio.jpg

[TownsendsFJR1300]

Okay. Learned my lesson for the day!

Basically it's bleeding off excess voltage quickly when the relay is turned off, to prevent excess/extra voltage going thru the system.. (I think..)

[mjm-1957]

Basically a clamping diode?