Re: Mariner V6 135 trim sensor
Steve;
First of all, here is the parts listing for your engine which is a model 7135412S:
http://www.mercurypartsexpress.com/ca/parts-search.html#epc::mc4952275mr1403
If you look under Reed Block and cylinder Head, you will see item 13, the Stbd temp sender and item 28, the port temp sender.
I presume that you have identified both of these on your engine and these are the two temp senders identified as items 12 and 13 on the electrical schematic which you have.
With these senders you have the option of connecting to a warning horn, gauge and optional visual warning device (light).
Can you confirm that you do have both temp senders installed because it will determine which one goes to the horn. Normally the tan/blue wire from the stbd sensor (basic on/off switch) will travel through pin 3 of the harness to the horn and the tan wire from the Port sensor (variable like a dimmer sw. in your house) will travel separately outside of the main harness to a temp gauge and/or warning light
Just to confuse things a bit more, here is a clearer schematic from a manual one up from yours but virtually the same wiring:
http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/878079/2d.pdf
See Pg 2D-19
And to confuse it even more, here is a link to various Mercury Control boxes to help you identify which one you have:
http://www.4shared.com/document/Gsz8M-KN/Merc_Controls_Newest_manual.html
I apologize if this is confusing but if you can determine that you do have both sensors and have identified their tan and tan/blue wiring, we will be getting closer.
Gerry