Nav lights create buzz sound on vhf.

[LG111]

Hi Everyone, as the title says. Where should I look first to figure out the electrical problem?

Thanks

Mark

 

[JVM225]

Is the radio sharing a ground with the lights? If so, try separating them.

 

[hottoddie]

Are the lights standard halogen or are they leds? Checking and or separating grounds sounds like a good start.

 

[Bob & Sue]

It may be as simple as your nav light wires running to close to the vhf unit or wiring & antenna wire and the above.

 

[LG111]

The lights are standard bulbs not leds.... yet...

Thanks for the ideas! I will start with the found and if wires are just to close to each other!

I'll report back. Thank you.

 

[Steve Craig]

Weak diodes in the alternator will, at times, let radio interference/static into the 12V system.

 

[LG111]

Okay, did a bit more hunting. I didn't see any real issues with ground wiring. Everything looks to be stock wiring set up. However, with running lights on and the dash dimmer down to off, no buzzing from vhf. But if I increase the dimmer the buzz comes back with changing frequency as the dimmer increases the dash light. So it must be something to do with the dimmer switch or lights on bezel.

Additional ideas?

Mark

 

[hottoddie]

Is the dimmer located near the VHF? Might be worth replacing the dimmer first to see if that helps. If it doesn't maybe relocate it.

 

[War Eagle]

It's likely the noise you are hearing on the VHF is being generated by the dimmer(or EL supply) - not the lights.

Is this a new problem? Was the VHF ever quite with this dimmer in use? Are the lights down stream the dimmer Electroluminescent?

Most solid state dimmers have some sort of filter to reduce the noise which is often inherent in the design.

 

[LG111]

The boat is new to me last March. First time I ran at night since it's dark at 5pm in the nw. The vhf is new 2012. The switch is original. I'll look into if there is a newer dimmer version as a replacement first...

Thanks!

 

[JVM225]

Okay, did a bit more hunting. I didn't see any real issues with ground wiring. Everything looks to be stock wiring set up. However, with running lights on and the dash dimmer down to off, no buzzing from vhf. But if I increase the dimmer the buzz comes back with changing frequency as the dimmer increases the dash light. So it must be something to do with the dimmer switch or lights on bezel.

Additional ideas?

Mark

The rheostat (dimmer) may, or may not, be the problem. It restricts voltage as you turn it down. That's how it makes the dash lights dim. When you turn it all the way down it usually cuts off voltage completely, hence the no lights when all the way down.
Anyway, you may want to try bypassing, or temporarily eliminating, it first to see if the problem goes away.
There should be two wires connected to it. Just disconnect them from it, and connect the two of them together. That will make the dash lights stay on at their brightest.
If the noise on the radio goes away, then you know it's the dimmer. If not, then you know it's no the problem.
If the noise persists, then the next thing to do is to disconnect the power and ground leads for the radio from wherever they are presently getting power and ground from, and then connect them to another source for power and ground.
The fuse block/panel that your other electronics are getting power and ground from would be a good place to connect them.

 

[LG111]

Thanks JVM! I will definitely try your plan.

 

[Knot It]

Did you find a solution? I have the exact same thing happening but with my stereo. It only buzzes when I turn the nav lights on but if I dim the dash lights down the buzz goes away. Have you been able t o find a replacement for the dimmer switch?

 

[JimT]

Did you find a solution? I have the exact same thing happening but with my stereo. It only buzzes when I turn the nav lights on but if I dim the dash lights down the buzz goes away. Have you been able t o find a replacement for the dimmer switch?

A ground loop isolator will clean up the whine/buzz on your stereo.