Nav Light Power and Warning Buzzer
 

I have a 1995 Mariah Talari, and I'm having electrical issues. When I turn on my nav lights, I get no light at the bulb, and I get a low tone on the warning buzzer. I also get the low tone and no function if any other switches are activated. (ie, blower, pump, court lts, etc) If I apply voltage at the nav bulb terminals, (no battery connected) all switched items work correctly, and no warning tone. Help. No schematic for this model is present.

Re: Nav Light Power and Warning Buzzer
 

Sounds like some sort of short or ground issue. The engine warning buzzer and the nav/dash switches are two different circuits, which makes me think your common ground might be at fault. Corrosion on wires and connectors can be somewhat of an issue on our boats, most of the time it's just as simple as removing the wire, cleaning the contact, and re-attaching.

Could also be a fuse issue?

Since you're a silver contributor (Thanks, BTW! :) ) You should have access to the Original Mariah Manuals & Supplements section. We have the wiring schematics uploaded there. The newer schematics start at '96, but you should check out the "Mariah Wiring Schematic for Older Models", as these were part of the original owners packages delivered with the boats. Hopefully it could point you in the right direction, or at least get you started. I'm sure some others will chime in with their ideas/experiences.

Re: Nav Light Power and Warning Buzzer
 

Thanks for the feedback. I did see the manuals section and the closest schematic I could find was the Diablo. None of "older" schematics showed the warning buzzer. I searched for a detached ground wire last night. The fuse block is not grounded to the boat, but has lots of open grounding spades. Couldn't find any unattached black leads. I also disconnected the connector going to the instrument panel, and the indicator lights on the switches would come on, but nothing would function.

I'll try some grounding experiments.

John

Re: Nav Light Power and Warning Buzzer
 

The warning buzzer is part of the engine's wiring system, which is separate from the boat's electronics. There's 3 sensors that will activate the warning alarm, oil pressure, engine temperature, and gear lube level. Those sensors are wired with a tan wire with a blue stripe. If you need the wiring schematic for the engine, those are located in the factory service manuals located in the "Service, Repair & Operating Manuals" section in our Maintenance & Repair forum.

Re: Nav Light Power and Warning Buzzer
 

Sorry, but I couldn't find the engine schematic. I searched the Maintenance and Repair forum.
I checked the grounding of the fuse block, and the switch assembly back to the negative battery terminal, and had continuity all the way. I really thought that this was a grounding issue after you suggested it. The buzzer is much quieter when I try to activate any of the switches, compared to the loudness when the ignition is turned on, like I'm getting a reverse voltage bleed of some sort. Any other ideas? BTW, the engine starts and runs well, And the instruments all respond. However the down trim doesn't work completely from the throttle switch (can't get full down trim). The stern switch raises and lowers the outdrive correctly.
John

Re: Nav Light Power and Warning Buzzer
 

Hi John,
Most boats are fairly similar so the lack of a schematic shouldn't hurt too much in an attempt to isolate your electrical problem. There is usually a fairly large gauge (#10 AWG) set of wires that brings B+ and B- from the battery in the rear of the boat up to the dashboard area of your boat. These wires usually feed the fuse or circuit breaker panel. Do you have a voltmeter? If so, using a long piece of wire connect one end back to the negative terminal of the battery. Use this wire as the reference to make all your voltage measurements under your dashboard. With all the switches off, what is the voltage of the large red B+ wire under your dash, what is the voltage of the large black B- wire? Now turn on one or all of the switches and repeat the measurements. Let me know what you find.
Steve

Re: Nav Light Power and Warning Buzzer
 

Ok, I went through the test you suggested and found proper voltage on V+ and leakage on V- of 32MV. So I saw the horn, and thought I'd try to connect a ground from the battery to the negative of the horn. I did and the horn and all other components worked also. So I connected from the fuse block to the horn, and all worked again. Because the negative lead to the horn was such a small wire, I decided to follow the negative lead to a ground junction, and check it there. Again, it corrected the problem. So I opened the junction and added a good heavy wire and ran it to the fuse ground. All is working correctly. I never traced the original ground so I don't know where the actual problem is. Thanks for the good advice.