Strange Electrical Thing Happening

[Old Vet]

I know this should probably go in the Electrical forum....but I just thought this one gets more viewing so......

A peculiar thing happens on my boat. I haven't yet tried to dig deeply enough to determine the cause exactly....but wondered if anyone here had any thoughts on it. I've determined the source....just not the cause yet.

My volt meter...and a couple of the other gauges pulsate.....whether the boat is running.....or not. Turn on the key....and away they go.......exactly like a pulse....at I'll guess around 80 - 100 pulses per minute.

So it puzzled me...scratched my head wondering what the heck was causing it. Then finally discovered that it only happens when my water system is turned on.

There are no sounds at all like the water pump cycling on the pressure switch to maintain system pressure. No water is being used. When first turned on...the pump runs...pressurizes the system...shuts down...and that's it.

Then that steady pulse on the gauges.

Very odd to me. Anyone have any ideas why this might be happening? What could cause this?

 

[electricaldoctor]

Are you talking about the AC or DC volt meter that flutuates and by how much? I assume that you mean the DC meter. Are all of the other breakers turned off when this occurs?

 

[JerryS]

Ok, here is my WAG. The pump or the pump wiring is shorting to ground but is not drawing enough current to open the circuit breaker. I would say to look at the pump wiring real close for any signs of arcing at butt connectors or any indications of chafing or arcing of the wiring.

 

[moparlvr4406]

sounds like a diode out causing a feedback in the system
or a corroded ground.

 

[MaddyDean]

Also disconnect the pump and turn the water system on--see if it still happens.

 

[JimG]

Also disconnect the pump and turn the water system on--see if it still happens.

++1

 

[1956olds]

try turning off your charging system and see if it still pulses.

 

[Old Vet]

"Are you talking about the AC or DC volt meter "

I....I should have said.....the volt meter on my dash at the helm