Digital trim trouble shooting

[minnowlimo]

Ser# OT651988 250xs
Problem I am trying to resolve is after moving trim the reading floats around on mercmoniter before finally settling on a #. It may take 5 seconds other times 20 seconds for it to finally decide where it wants to read at. It may be at 5.2 bump trim up and it up to 5.1, bump it again and we are at 6.1? When trimming all the way down sometimes It lands on 0 sometimes 0.4 or 0.2 It doesn't get to far off track but definitely not consistent.


1- verified I have digital 3 wire sender.
2- I have calibrated trim multiple times
3 took 3 wire bullet connectors apart, cleaned and added dielectric grease
4-removed sender to look for broken unusual parts.
5- looked wiring over for cuts and abrasions

I have looked back through previous threads stating check ground at swivel bracket. Exactly where is this located? Looked 'all over port side. All grounds appear to be fine. Anyone have a pic of where it is? Is their a way to test sender ? Thanks

[Savage]

Check cross pin bushings.
Check trilobe pin.

[minnowlimo]

Are we talking about the rod where the trim ram hits and the bushings on either side of where they hit the bracket of motor. One side would have the digital sensor on it?

[Savage]

Yes. Starboard bushing fall out sometimes. Trilobe pin holds the shaft in place.

[minnowlimo]

Well turns out mine has a lot of play in it. Either they are wore out or have fell out. I will try and pick some up tomorrow. Thanks savage

[Savage]

Install new bushings with Loctite......I use loctite 680.

[minnowlimo]

Thank you sir

[EuropeanAM]

Be sure to report back on results.

[minnowlimo]

Replaced bushings, the old bushings where still intact ( hadn't fell out) after replacing them running the trim in the shop it still does the same thing. I am thinking I need to replace trim sender?? I have calibrated a few times with same results. In this video we are starting at full down and bumping trim in the UP only.

Calibration process
Trim down - all the way down
Max trim- this is at the point where trim changes speed.
Trailer point - trim will not go any further up.
Correct?? ^^

[minnowlimo]

Got out today to check a few other things and to make a short video of trim while running. Trim is in bottom left of screen. You can see how bad it is jumping around. You can be in perfectly flat water and it still does it. But it will hold true to full trim down even while running. Sorry about crappy video but you get the point.

[EuropeanAM]

Please check (third, fourth, fifth, whatever it takes) the wiring for the digital sensor.

NOTHING should be plugged into the BROWN w/WHITE STRIPE wire. ONLY use the Blue, Yellow, and BLACK w/Orange Stripe wires on the engine side.

IF YOU MIX THE BROWN w/WHITE INTO THE WIRING- THIS WILL OCCUR.

[minnowlimo]

I'm lost like a ball in high weeds at this point. I must be missing something simple. Here are some pics. What am I missing here? I'll pull lower pan and take more pics if I need to.

3 wires coming from digital trim sender to factory wiring harness

Wires not connected from mercmoniter harness^^


Thought I knew what I was doing but that proved to be wrong. Thanks

[minnowlimo]

Ok don after pulling the pan and searching everywhere this is the only brown with white wire I could find (not plugged in). I went and looked at another newer optimax with mercmoniter system and it appeared that the 8 pin harness that the trim sender plugs into was a little different. Thanks a lot hagen

[EuropeanAM]

Hagen- it appears that you are wired correctly.

Just to be sure- pull the 3 wiring (bullet) connectors apart, clean them, and then reconnect. Also inspect the metal connector crimps for any evidence of wire breakage (that would cause intermittent operation).

[minnowlimo]

Well after searching every square inch of the system, wiggling wires, checking and cleaning connections i finally just replaced the sending unit. Now all is fine thanks savage and don for all the help.

[Savage]

[sodaksker]

I have found this thread helpful. Thanks for the information. Just curious, which piece in the pictures is the actual trim sending unit?

[Savage]

I have found this thread helpful. Thanks for the information. Just curious, which piece in the pictures is the actual trim sending unit?

The trim sending unit isn't in the pictures posted here.

[EuropeanAM]

The first picture in Post# 12 shows the WIRING CONNECTORS for the Digital Trim Sender (sender is not pictured, however).

[sodaksker]

I think I found mine. Is this it?

If so, what kind of cost are we looking to replace it?

Thanks