Voltage Feedback

I am installing a new OMC tach on a 16 foot Smokercraft Alaskan (1997). The tach wireing harness has three connectors that go to obvious lugs on the back of the tach. But the lug for the tach light is separate.

The instructions that came with the tach say to hook the lights wire up to the boats "accessory" terminal. I have an Accessory switch but no terminal. No problem I just located the terminal on the switch that was dead when the switch was in the Off position and hot (13 + volts) when the switch was in the On position.

Using a snap connector I tied into the appropriate wire then plugged it back into the switch. At this point I noticed I had a .4 volts reading on the wire when the switch was in the off position. I disconnected the wire from the switch and discovered that there were .4 volts in the wire when not connected to the switch. So I did not hook it to the tach.

I appear to be getting some voltage feedback from somewhere. Is this normal.

Under the switch there is a "Reset" button. Should I have connected my new wire to that instead of the switch?

Appreciate any help!

Re: Voltage Feedback

Not sure what you are connecting to but instrument lights normally get connected to the switch that controls the rest of the lights (blue wire). If you want the tach light to come on when the key is on then connect it to the purple wire on the switch.

Re: Voltage Feedback

Thanks. Apparently Smokercraft did not get the memo - there are no blue wires of any shade behind the dash (not even wires with blue stripes), not a problem though I can tie into the switched fuel gauge light (purple wire). That should work.

The more important question is there any reason that I should be getting a reading of .4 volts on a wire that should be dead?

There are no accessories installed on the boat beyond navigation lights, fuel gauge, bilge pump, and a plug for accessories (nothing is plugged in). All have separate dash switches. The fuel gauge has a light that comes on when the dash switch is turned to the On position other than that there are no dash lights.

Re: Voltage Feedback

If that is the gray wire showing voltage, you may need to test your rectifier. Go to the Engine FAQ forum and look for the thread by Joe Reeves on how to test.

Re: Voltage Feedback

The wire is colored orange and dark brown. The Smokercraft owners manual says it is "All pumps circuit protection". I only have one pump, the bilge pump, at it is not wired into this circuit. I have started tracing the wire and have figured out it does not go to anything in the rear of the boat. So now I have to pull the floorboard in the bow and see where that leads.

Thanks for the advice.