Electronic trim issue

[KDAVID1]

My electric trim has a mind of it's own. ;It's a 1993 mercury 150hp xr6. Has a 3 way toggle at the bow, one in the throttle lever, and one on the cowl. First trip out this weekend since August and running down the lake at 55mph and it started trimming up on its own. ;Had to shut her down. I had to keep the throttle trim pressed down while my buddy used the cowl trim to trim it back down.;It did this a few times then was normal. ;We got the boat loaded and i disconnected the battery.Where do i start... throttle, bow, or cowl; What is the best way to trouble shoot?;Thanks in advance.

 

[Silvertip]

To eliminate a switch problem, disconnect the switch at the cowl and at the bow. These switches are parallel wired so the one on the throttle should still work. If the problem still exists, do not assume it is the switch on the throttle lever. You can jiggle/tweak that switch while under way to see if it is intermittently activating the trim. Since the throttle trim didn't appear to trim the engine down but the cowl switch did, that points to a problem with the throttle switch or wiring in the box itself.

 

[gm280]

Not knowing the actual setup, do those switches go directly to the trim motor or to a soloed(s)? I ask because if it goes to a solenoid(s), that /they could be suspect as well. JMHO!

 

[KDAVID1]

Thanks guys. I did find out while on the water the switch at the bow was parrelle ;It's a 91 ranger 354v and stock so not sure if it has a selenoid. ;I'll try what Silvertip mentioned soon as the rain goes away and provide feedback. Thanks again fof the help.

 

[KDAVID1]

Ok I've determined it is the throttle switch.  Button is actually a bit loose as well.  A: how in the world do you get that switch out of the handle to change it?  B: How do you get the whole handle off?   Heck i can't even get the box off.  Screws just turn...must have nuts on the back side?

 

[KDAVID1]

Just to follow up.  I got it torn apart and switch on the way.  Once the box was dismounted the bolt holding the handle on the box was accessible.  All good from here.