Trim Went Up On Its Own and Won't Work Now

[Cliffprocraft190]

I have a 1998 175 HP Merc EFI. Serial Number OG724742 After going to a lake today that is on a dirty, dusty road, I went to the car wash on the way home and washed the dust off. Went to a place to eat about a block down the road ... came out and checked on the tires and didn't notice anything out of place. Drove down the road about 20 miles and noticed that my outboard motor was not straight, which was not right because I use a Motormate support which normally holds it rock solid and straight, so I pulled off into a rest area to check things out and the motor had trimmed all the way up and the Motormate was hangin loose. I went to put things back like they should be and none of the trim switches would work ... not the one on outboard, not the one on the shift control, not the one on the bow panel. Nothing: like there was not power. What is the likely culprit? Did water short one of the switches out at the car wash? Is there a fuse inside the cowling somewhere or a trim solenoid? Would the cylinder have "hit top" and burned up my trim motor?

[EuropeanAM]

Moving your thread to the 2.5L Forum (correct location unless you have a 4-stroke).

Bow or Cowling Switch are two likely culprits- there are fuses for the power circuits, but that's going to depend on which engine you have.
Most have fuses somewhere on the STB side of the engine, either in an inline fuse holder (single fuse) or in a small fuse holder mounted to the electrical plate somewhere.

Please update with the engine serial number and someone will be glad to assist.

[Cliffprocraft190]

TTT

[JOE54]

better test electric mtr now might be toe up

[EuropeanAM]

Should be a 20 amp fuse in an inline holder, near the starter solenoid on the STB side of the engine. That fuse supplies power for the keyswitch harness (including trim switches).

[Cliffprocraft190]

20200819_185533.jpg20200819_185822.jpgHere are some pics showing an inline fuse holder with a 20 amp fuse on starboard side near the starter (sorry it is sideways). Is that the one you are referring to? I checked that fuse (20 amp) and it appears to be OK. What is the round device in the second photo? Port side, near lift cylinder.

[leonreno]

The round device is the trim position sensor, for
the trim gauge.

[Cliffprocraft190]

The round device is the trim position sensor, for
the trim gauge.

Good to know for future reference! Thanks!

[EuropeanAM]

Does the STARTER function? If not, test the fuse with an ohm meter.

[Cliffprocraft190]

Does the STARTER function? If not, test the fuse with an ohm meter.

Yes, the starter works.

[JOE54]

you test elect mtr yet ^^^^^#4

[Cliffprocraft190]

you test elect mtr yet ^^^^^#4

Not yet. Hoping it was just a simple deal like a fuse or trim switch. Will start checking switches, then motor. Thanks.

[Cliffprocraft190]

you test elect mtr yet ^^^^^#4

Tested front (bow panel) trim switch and trim switch on side of outboard with multimeter. They checked out OK. Have to figure out how to get to trim switch on shift lever. It's a Phillips head but not enough room for a stubby or offset screwdriver. If it is OK, then I guess my trim motor is fried? Where do the leads from the trim motor attach to the outboard? I guess the way to test the trim motor would be to take the leads off the outboard and connect them direct to a 12V source so that a switch is not involved? Are there any trim solenoids or relays involved to check?

[Jim1752]

You need a wiring diagram! Jim sheetz

[JOE54]

relays yes, wires should just unplug at connectors ,can test with vom also at connections

[Cliffprocraft190]

relays yes, wires should just unplug at connectors ,can test with vom also at connections

Are these two cubed shaped devices at the bottom of the photo, the trim relays? The have 5 blades in each one. How do I go about testing them? I took them apart and sprayed with electrical connector cleaner and then put them back together. Still no trim.20200826_191956.jpg

[EuropeanAM]

Plan to simply replace them if you "took them apart and sprayed them with contact cleaner".

Test the trim motor, as Joe54 recommended way back in Post#4. It's a simple polarity-reversing system (12V+ to one wire, 12V- to the other and the motor should operate).

Reverse connections and it should operate the other direction.

If your results don't match, it's DOA.

[Merc2.4]

Testing at trim switches isn't doing you any good , do as joe and don said , gotta go straight to motor then u can work urself out to the issue ,

[Cliffprocraft190]

Plan to simply replace them if you "took them apart and sprayed them with contact cleaner".

Test the trim motor, as Joe54 recommended way back in Post#4. It's a simple polarity-reversing system (12V+ to one wire, 12V- to the other and the motor should operate).

Reverse connections and it should operate the other direction.

If your results don't match, it's DOA.

OK. After cutting a couple of zip ties and parsing the wires out for the trim motor, I find that the trim motor works up and down and nothing wrong with the trim motor. So I guess it's either the trim relays and/or a trim switch that is bad?

[Cliffprocraft190]

Testing at trim switches isn't doing you any good , do as joe and don said , gotta go straight to motor then u can work urself out to the issue ,

I found that the trim motor works.