Cigarette lighter problem

[sbmcruise]

The cigarette lighter outlet that I power my small Garmin hand-held GPS (atrox Legend) from had gotten cranky and upon inspection I could tell that the center contact was badly corroded. I tried to clean it with limited success.

I purchased and installed an identical cigarette lighter outlet, but it won’t hold even a minimal load without the voltage dropping to 4-5 volts. This happens when I plug in the GARMIN power cord, a 2-way cigarette adapter, or any other very small load devices. With no load on the cigarette lighter outlet I have 12.8 volts or better (depending on what the onboard charger is doing), but adding any of these very small loads radically drops the voltage. Power is supplied to the cigarette lighter outlet via an accessory bus that also powers the navigation lights, fishfinder, livewell pump, bilge pump. I can turn on any or all of these accessories and the voltage on the bus does not change, so the bus can handle loads bigger than what I am supplying at the cigarette light outlet. I have tested the cigarette lighter outlet and its wiring harness on a regulated power supply in my shop and everything functions properly there. In that environment none of these accessories causes any measurable voltage loss when powered-up directly from the regulated power supply or through the cigarette lighter outlet driven by the regulated power supply. This tells me that the accessories are working normally and do not have shorts that would explain the voltage drop.

I purchased and installed a different brand cigarette lighter outlet with a completely different construction and with a completely new wiring harness back to the accessory bus, but the problem remains the same.

I am out of ideas and need suggestions.

Thanks

[Sea_Dad]

what shape are the wires in feding the 12 volts to the outlet? A bit on the green side maybe?

My first suspicion would be corroded wires, poor crimping, or wire too small to carry the current in the first place. I didnt here you mention fuses or breakers for this outlet either. Protect the wires running to that outlet or they will show you just how bad a day you can have on that boat.

[colliwh]

I'm with SeaDad......first thing I would do is replace the wires from the buss to the lighter socket. In fact, I think I would first make a wire set and jumper them between the two before proceeding with a "tidy" installation just to be sure that was the issue. Since you had corrosion on the old plug, that may be what you are dealing with again.

[sbmcruise]

There was no visible corrosion in the wiring between the Cigarette lighter socket and the accessory bus, but I cut the ends off (no corrosion on bare wire) and crimped on new ends. The second socket had its own new wiring and I crimped on new ends there also.

The wiring is 10 inches long and 14 guage.

There is a 15 amp fuse at the accessory bus protecting the circuit. Changing this out with a new 30 amp fuse did not improve things.

There is no visible corrosion on the assecorry bus connectors (slide-on males)

[Sea_Dad]

Try putting a multimeter on the acc. bus itself and plug the load in, if it's pulling down in voltage too, then the lighter is the culprit.

[sbmcruise]

Part of my diagnosis was bad. The accessories on the switch panel are not dependant on the accessory bus, but have a daisey chain arranegment and the accessory buss gets its power at the beginning of the switch panel. There was corrosian at the connector at the switch panel. I cleaned the male connector and replaced the female connector and the wire to the accesory bus. All better now.

[Sea_Dad]

velly nice.

[baypro21]

Don't forget to change that fuse back to the proper amperes

[Kamper]

You now know more about your boat*and learned it in a safe place.

Also you now have a spare part for the nect time, unless you install it as a second power-port. FYI - I installed my power-ports in a*location shielded from the elements.