Not absolutely necessary but I would.

Newbee question, the cable is not short circuit due to having 0.36V thru
the whole harness. So if I test continuity, what will I found out?

You're looking for a possible high resistance such as might be caused by a corroded contact or broken/near broken wire. There should be 0 Ohms to maybe 2 Ohms max from the box end of the 5 volt circuit to every sensor grey wire connection.

Hmm.. I have 2 Ohms from all the connectors to the grey wire at the box. .
Also 2 Ohm between the grey and ground.

0.36 volt from grey to all the ground points i can find in the boat. .

Short circuit in the trim sender caused the 5V harness to malfunction.

Now everything is working as it should!

Thank you so much for the help!

That was the big clue. Good job, glad you found it. Everyone learns from this kind of stuff. The trim sender isn't connected to the computer on my boat. I wouldn't have guessed that.