Trim and tilt problem

[Dennyg]

I have a 1997 Mercury EFI 150 hp outboard, serial #0G508578 After I put my boat in the garage I lowered the motor almost fully in the down position.
About a minute later the trim/tilt motor started running. I pushed the trim/tilt button on the side of the outboard and it stopped. I ran the motor up and down a couple of times
and about a minute later it did it again. I have three trim/tilt buttons, the motor, throttle and bow panel.
I had the trim/tilt switch on the motor replaced less than a year ago. I disconnected the battery cable to avoid burning something up.
Any ideas on the cause of the problem?

[EuropeanAM]

Likely a switch with corrosion in it (or water in it). While not impossible for it to be a relay, it's not nearly as likely for that to be activating "on it's own".

Disconnect the power from the bow switch, and from the cowling switch, and monitor to see if the problem occurs. When you're confident it's not happening, re-introduce the switches one at a time.

Also be sure to visually inspect that bow switch. Often there's visual evidence that will substantially shorten your process of elimination.

[Dennyg]

Likely a switch with corrosion in it (or water in it). While not impossible for it to be a relay, it's not nearly as likely for that to be activating "on it's own".

Disconnect the power from the bow switch, and from the cowling switch, and monitor to see if the problem occurs. When you're confident it's not happening, re-introduce the switches one at a time.

Also be sure to visually inspect that bow switch. Often there's visual evidence that will substantially shorten your process of elimination.

Thanks, I'll give it a try.