Wire cut 175 merc

[jdp8488]

The wire on the starboard side comming off the thermostat cover is cut. It is tan and blue. The same color wire on the port side of the motor pn the other thermostat cover is not cut, and its hooked up. I believe this is for the overheat warning horn? I have not run the motor in the river yet because I am still working on the boat. It runs great on muffs though, but have not water tested.. Just wondering why it would be cut and where to hook it back up at. Thanks for any help. -Justin

 

[Rocky_Road]

Re: Wire cut 175 merc

The wire on the starboard side comming off the thermostat cover is cut. It is tan and blue. The same color wire on the port side of the motor pn the other thermostat cover is not cut, and its hooked up. I believe this is for the overheat warning horn? I have not run the motor in the river yet because I am still working on the boat. It runs great on muffs though, but have not water tested.. Just wondering why it would be cut and where to hook it back up at. Thanks for any help. -Justin

Not sure if this is any help to you...but, the tan/blue wires on my Mercruiser 3.0L are dedicated to the audible warning buzzer circuit. My engine has these wires unused, and when I grounded them (key in the 'on' position), the dash mounted buzzer came to life. I am in the process of installing the necessary oil pressure, water temp, and outdrive fluid level switches to make this audible warning system functional.

It would surprise me if Mercury didn't use the same color coded wiring, for all of their product lines....

 

[JUSTINTIME]

Re: Wire cut 175 merc

what year is this
most motors have overheat on each side

 

[jdp8488]

Re: Wire cut 175 merc

Its an 86. It does have it on both sides I am guessing? On the port side, the wire is connected. The starboard side is where it is cut. I have no clue where to hook it up, or why it may have been cut other than the horn constantly going off. Just wondering if this could be a problem, with this cut, I have no warning horn if it starts overheating, right? Thanks for any help.

 

[JUSTINTIME]

Re: Wire cut 175 merc

you will need to find it
find the other good one so u know what 2 look 4

 

[jdp8488]

Re: Wire cut 175 merc

Find the other what? Would the wire that was cut just goto the same place as the good wire?

 

[JUSTINTIME]

Re: Wire cut 175 merc

temp sender

 

[Rocky_Road]

Re: Wire cut 175 merc

Did you mean the temperature switch?

The temperature sender usually uses a solid brown wire...varying voltage, to feed a temperature guage. The tan/blue wire is usually connected to a temperature switch...simple 'go..no go' setup. The temperature switch activates when a overheat situation is detected.

Why wouldn't a simple testing of his cut tan/blue wire to engine ground (key switch in run position) determine it's purpose? Assuming that his audible warning buzzer is in place, and functional?

Just a thought....

 

[jdp8488]

Re: Wire cut 175 merc

So, just ground that wire off while the key is in on position and see what happens?

 

[Rocky_Road]

Re: Wire cut 175 merc

So, just ground that wire off while the key is in on position and see what happens?

Exactly!

If you have a circuit tester, you can use it to see if the cut tan/blue wire has current, first. The tan/blue wires on my engine are current fed, with the key in 'run'. If you don't have the circuit test light...then simply ground the wire to the engine.

I would also test ground the connected one you mentioned...if the buzzer works, when grounded, then you have some degree of protection. It could be that the cut one was going to a faulty temp switch...and the owner found it easier to simply disable that particular temp switch. Not my way to correct an issue...!

Mercury temperature switches, for the audible warning system, are sold on eBay. The come in two color codes...red, and black. My Mercruiser 3.0L uses the red one, and I have one coming. The black one triggers at a higher temperature, and seems to be used on the 6 and 8 cyl I/Os. You should look to the connected tan/blue wire, and see what it is connected to.