Gauge lights

[joel45acp]

The lights on my gauges don't light up. The gauges do work, but the bulb doesn't light up. I'm only getting 3.01 volts at the bulb contact points. The bulbs are good. I'm at a loss here folks. Any info would be greatly appreciated.

 

[rwidman]

Re: Gauge lights

The lights on my gauges don't light up. The gauges do work, but the bulb doesn't light up. I'm only getting 3.01 volts at the bulb contact points. The bulbs are good. I'm at a loss here folks. Any info would be greatly appreciated.

If you are measuring the voltage correctly, there is a resistance in the circuit. A corroded connection is the most likely cause.

Trace the wires, find the problem, correct it, and your lights will work.

 

[Silvertip]

Re: Gauge lights

You know its NOT a ground problem because if it was, the gauges would not work. It is a power feed problem from the NAV/ANCHOR switch. Start there. Look for 12 volts into the switch and then check out of the switch. If the two lights work, then move on from the switch to the first light in the system. Since none of them work, I'm betting the first light connection is bad.

 

[rwidman]

Re: Gauge lights

You know its NOT a ground problem because if it was, the gauges would not work. It is a power feed problem from the NAV/ANCHOR switch. Start there. Look for 12 volts into the switch and then check out of the switch. If the two lights work, then move on from the switch to the first light in the system. Since none of them work, I'm betting the first light connection is bad.

On my boat, and my previous boat, the lighting circuit is totally seperate from the gauges and their circuitry. Both positive and negative. I have to assume that some other boats are wired this way.

 

[Silvertip]

Re: Gauge lights

Good clarification. Agree that some boats had separate internal lighting ground and that this could indeed be the issue. If this is a newer boat however, the lamps are probably the the twist in type where the bulb snaps into a plastic holder that inserts into the gauge. That type of gauge utilizes a common ground for both the lamp and the gauge movement. No wires are used on those lamp holders as they there are just two tabs that contact circuit paths on the gauge.