Trim and Tilt on 2008 Yamaha 300 HPDI

[Txbass12]

I've got an '08 300 HPDI with trim and tilt issues. The relay has power and clicks when the trim switches are pushed. Its the same result regardless of which trim switch is tried. I bypassed the relay and the trim motor checks out fine for both up and down so I replaced the relay. After replacing the relay I figured it should be good to go but the problem wasn't fixed, I still have the clicking of the relay and no activation of the trim motor. So, I got ahold of someone with the same motor and swapped out relays between motors. The relays that didn't work on my motor worked just fine on the other one. Re-installed back on mine and back to the clicking and no trim. I'm assuming this is a ground issue when the relay is activated. I have made sure all battery connections are clean and tight. Am I missing something obvious, what else should I be looking for and is there some sort of work around to at least use the boat with a functioning trim and tilt until it gets figured out? This motor is on a 2008 Skeeter 21i bass boat.

[99yam40]

I would think at this point I would be measuring the voltages into and out of the relay

[Txbass12]

Looks like 12.8 volts in and 12.7 volts out when I go black to green or black to blue. I'm no service tech by any means and had help earlier. What is this possibly indicating?

[99yam40]

Is that across the motor leads or the control wires

[Txbass12]

Thats at the leads at the relay

[fairdeal]

this a strange one.

the relay (which is actually two separate relays)
has two ground connections -

a small black wire, for the relay coils -
which you know is good, because the relays 'click'

a large black wire, for the t/t motor itself.
Both the blue and green motor wires should always be connected to that ground
except when the relay actuates -
then one of them is removed from ground and given power.

at the relay,
check with a meter between the nut with the big red wire
and the nut with that big black wire -
you should have continuity.

alternatively,
remove either of the motor leads -
the big blue or the big green -
from the relay, and connect it to power -
the t/t motor should run.
If it doesn't, that ground is not present.

[99yam40]

Thats at the leads at the relay

which leads?
the ones going to the T&T motor?
or the ones coming from the T&T switches to operate the relay?

looks like Fairdeal gave a good way to check things

[Txbass12]

99yam40 Thats at the blue and green leads going to the T&T motor. fairdeal I do have continuity between the big black and big red wires at the relay. I will do the other test you mentioned later after work.

[Txbass12]

alternatively,
remove either of the motor leads -
the big blue or the big green -
from the relay, and connect it to power -
the t/t motor should run.
If it doesn't, that ground is not present.

The Trim motor runs if I remove blue or green from the relay and put them to the red lug on the relay. Was that how you meant or run separate power to blue or green?

[fairdeal]

The Trim motor runs if I remove blue or green from the relay and put them to the red lug on the relay. Was that how you meant or run separate power to blue or green?

that's exactly what I had in mind, as the easiest.
But that makes the situation even more puzzling;

you've now done exactly what the relays do:

remove either the green, or blue, wire from its connection to ground,
and connect it to the red lug.

That the motor runs, proves that you have both power and ground at the relay.

So why does the relay itself not make that connection,
when actuated by the t/t switch -
even though you hear the relay 'click'?

sorry - I'm baffled.

[Txbass12]

Baffling for sure but I appreciate your help. Everything points to the relay and I wish it was that simple! Any possible workaround? Granted I can use the boat as is but its a hassle to say the least to manually run the trim this way but some sort of temporary fix or work around would be nice if it was electrically safe.

[boscoe99]

You need current flow through the relay control circuit to activate the relay contacts. One relay for up circuit. One relay for down circuit.

You need current flow across the relay contacts. Two contacts per relay.

Does this help?
image_5273.jpg

[Txbass12]

boscoe99 That diagram does help. I appreciate it. With that diagram showing the proper operating of the relay and circuit what am I missing on mine when I install an operating relay that works on another outboard and but not on mine? Is there some sort of bypass that would be safe? I'm far from a service tech! Thanks!

[boscoe99]

Have you fully tested the relay assembly?

What is the voltage at the relay when the up trim or down trim buttons are pressed?

[Txbass12]

Assuming I'm testing volts property when I go black to blue or black to green I'm seeing 12.7 volts when trim buttons are pressed. Beyond that is there another test to the relay?