2008 Yamaha VMax 225 Trim guage/sender ?

[WayneM1946]

I have the round Multi-function guage. The trim guage reads full UP regardless of where the motor is set. The little plastic tab that breaks all the time has already been replaced with a stainless steel one. I pulled that off to get it out of the way and I can move the arm on the trim sender with my finger and it does not appear to be sticking. It moves smoothly with some spring resistance but it does not affect the guage reading at all, it stays at full UP.

How do I test the sender and/or guage to determine which of them is at fault?

Wayne

[yam911]

To test the gauge jumper the gauge pink wire to a known ground. The trim should show all the way down. Disconnect the pink wire. The trim bars should move all of the way up.

To test the sender requires an ohm meter. In the full down position the meter should indicate ~ 33 ohms. If the full up position the meter should indicate ~ 240 ohms.

If both the gauge and the sender are OK then that indicates an open wire issue.

[WayneM1946]

OK, after I posted my question, I went to the shop manual and started to troubleshoot based on what was in there. To my surprise, when I removed the cowling to get to the pink and black wires, the connector that goes to the sender was not even plugged up. I checked across the pink and black wires that go to the sending unit and got 338 Ohms which is in the specified range for the full up position ( the arm that actuates the switch is completely removed from the motor.) I think that indicates that the sending unit is toast. Is that correct? According to the manual, it should have read 9-11 Ohms with no pressure on the sending unit arm and 238-378 Ohms in the full up position. The switch is not stuck, it moves smoothly but with some spring like resistance.

When I checked the voltage across the pink and black wires on the connector that goes to the guage (the connector that was supposed to be plugged into the sending unit switch) I get 5.1 V. I also checked the pink wire to ground and got the same 5.1 V. so I guess that means the black wire in the plug is making a good ground.

I have not done the test on the guage yet but I will do that tomorrow.

Why would the guage give me a full up indication if the wire that feeds it is not even plugged up?

[WayneM1946]

yam911, I just reread your instructions and now I understand why my guage is giving me a full up indication. The pink and black wires are unplugged back at the the connection under the cowl. I did check the pink wire to ground but was looking at the voltage and didn't look to see if the guage went full down. It is stormy here today, so I probably won't get it done today because I am not going to take the cover off the boat.

I am also concerned about why that connector inside the cowl was unplugged. Wondering if there might be an electrical problem with that circuit.

Thanks,

Wayne