Merc i/o trim position sensor wiring

[otgdy]

I replaced the trim position and up-limit switch on my '84 Alpha 1 outdrive. (Wellcraft 26ft Aft cabin)
Have the up limit switch and wiring setup and now I am looking ot hook up the
trim position sensor. Unfortunately I can't locate the wires in the engine compartment
that the two leads connect to. Found the up-limit wires are on the trim motor thanks
to one of the posts. In addition I can't find the wiring diagram for the position sensor. I am assuming
that one of the pigtails is a ground and the other goes to the gauge but would like to make sure
before I ground out the entire circuit.

Can someone help ?

Thanks
OTG

 

[achris]

Re: Merc i/o trim position sensor wiring

In addition I can't find the wiring diagram for the position sensor. [size=+1] I am assuming
that one of the pigtails is a ground and the other goes to the gauge[/size] but would like to make sure
before I ground out the entire circuit.

Correct... and it doesn't matter which is which...
Sometimes there is a wire in the engine harness to connect to, sometimes not.. You are looking for a brown/white wire...

Chris......

 

[otgdy]

Re: Merc i/o trim position sensor wiring

Correct... and it doesn't matter which is which...
Sometimes there is a wire in the engine harness to connect to, sometimes not.. You are looking for a brown/white wire...

Chris......

I see the brown/white wire at the guage but it disappears into a mess of wire. Instead of unraveling all the wiring I was hoping someone could narrow the search a little. i.e Wire goes down the starboard side or the wires go over to the trim pump. I know wishfull thinking. Thanks for the wiring info. Worse comes to worse I'll run another line.

Thanks
OTG

 

[Bondo]

Re: Merc i/o trim position sensor wiring

I see the brown/white wire at the guage but it disappears into a mess of wire. Instead of unraveling all the wiring I was hoping someone could narrow the search a little. i.e Wire goes down the starboard side or the wires go over to the trim pump. I know wishfull thinking. Thanks for the wiring info. Worse comes to worse I'll run another line.

Thanks
OTG

Ayuh,... It should come outa the loom aft, by the pump, near the transom assembly, where the new wires will reach too..

 

[otgdy]

Re: Merc i/o trim position sensor wiring

Ayuh,... It should come outa the loom aft, by the pump, near the transom assembly, where the new wires will reach too..

Thanks I'll do my bilge diving and let you know what I find. The previous owner just cut wires and left them in the bilge water. Wouldn't be surprised if these are in there also.

Thanks again
OTG

 

[achris]

Re: Merc i/o trim position sensor wiring

The previous owner just cut wires and left them in the bilge water. ...

Don't you just love professionalism... :facepalm:

 

[otgdy]

Re: Merc i/o trim position sensor wiring

LOL
Well I traced the brown/white wire to the solenoid on the starboard valve cover then who knows where it goes. I believe that solenoid controls the starter amongst other things. Perhaps I need power in order to make the final connection ? Does the trim gauge work with power off ?

OTG

 

[achris]

Re: Merc i/o trim position sensor wiring

Sounds like the PO didn't just cut wires. He may have had a problem with a wire in the loom and instead of fixing it properly, just grabbed another 'unused' wire and rigged that up....

I regret to inform that you may have to 'point-to-point' your entire wiring harness... :facepalm:

Chris.........

 

[otgdy]

Re: Merc i/o trim position sensor wiring

I have been going over all the different circuits and checking them out. That's part of the reason why the boat hasn't seen water in the 3 years I owned it. Rebuilt the entire outdrive, carb, fresh water system, trim pump. Not surprised you would say that. I am 100% positive the boat would have had a major fire had I taken it out. The PO was electrically challenged to say the least.
One question .. does the trim position work with the power turned off or is it like the other gauges that turn on/off ? Wondering where the gauge gets its power or does the starter slave solenoid complete the circuit ? I really need an electrical schematic for this boat. Anyone know where I can find one that includes all of the gauges ?

Thanks
OTG

 

[Don S]

Re: Merc i/o trim position sensor wiring

The gauge gets it power from the ignition switch, just like the rest of the gauges.

Here is a link to the service manual with the wiring diagrams for the engine. One note on the instrument panel diagrams. The B and I terminals are labeled backwards in the diagram. B should be the red/purple wire, and I should be purple.

http://www.4shared.com/office/mRjamBOE/03__Engines__All__78-84.html