Dim Mast mounted Deck Light

[Paulieb]

Hoping the electricians in the group can point me in the right direction.

I have a mast mounted deck/steaming light with wiring coming down the mast to a 4-prong connector which plugs into a receptacle on the deck.
The mast is currently in the trailering/storage position and I wanted to test the lights by hooking up the 4-prong connector to a 12v power source.
I have one of those emergency 12-volt jumpstart/tire compressor gadgets that also has a 12-volt cigarette lighter adapter, I then took a cigarette lighter plug and connected alligator clips to the +/- ends. I then used this to connect to the male pin end of the connector to apply power and test the lights on the mast.

This worked great for all lights accept the deck light - the fixture is a combo deck/steaming light - the steaming light works just fine. On initial inspection the deck light bulb was blown, so I ordered a replacement. After replacing the light bulb, I retested, nothing at first and then I got the faintest glow from the filament in the bulb (very very dim). The steaming light in the fixture works just fine.

I am assuming there is some corrosion somewhere that is robbing the current. I opened the connecter and there was some corrosion, but not a ton.
I ordered a replacement plug and deck fitting, but I figured I would throw it out here for any other suggestions.

Thanks to all

Pauleib

[Russ]

I have come to use CorrosionX for electrical fittings to keep junk out. Corrosion doesn't seem to be your issue if you have checked that.

Maybe the replacement bulb is 24v instead of 12v. Pull the bulb and see if it has the voltage printed on it. Try taking it out of the fixture and connect your clips directly to the bulb. Be careful if it's a halogen as they got hot and can be blinding bright.
I had one of those fixtures on my Hunter. Went through several bulbs until I got tired of climbing up to replace them.
When you DO replace a halogen bulb, they say not to touch it with your fingers as the oils and fingerprints can cause problems. Maybe that was my problem.

[Highlander]

sounds like a bad ground or no ground "open circuit" their r three wires 2 power for each light & 1 ground make sure both lights r grounded

J

[Tomfoolery]

sounds like a bad ground or no ground "open circuit" their r three wires 2 power for each light & 1 ground make sure both lights r grounded

I too would share the ground, and leave one conductor and plug/socket pole free as a spare. But given that it's wired already, I'd start by checking the DC resistance across both units, and if it's very high on the deck light, try tying the two grounds together and measure again. If still high, it's on the + conductor. If not, it's the ground. At least the OP will know where the problem is, and can take action from there.

[Russ]

If this is the fixture you have, it's the same one I had.

The deck light uses a ba9s 20w 12v halogen. Little bulb that was hard to install. As mentioned, check to see if it shares a common ground with the steaming light and ensure it's not corroded.

While you are at it, I would replace the steaming bulb with an LED.

[mastreb]

Sounds like it's the wrong bulb. You can check the wiring with an ohmmeter by disconnecting the plug from the deck socket, putting a jumper between the the +/- pins on the plug (to connect them together), and then using the probes on the ohmmeter to touch the ground and power leads in the light bulb socket itself. If you show low resistance (<10 ohms) you don't have a corrosion problem anywhere in the above-deck wiring.

[Highlander]

sounds like a bad ground or no ground "open circuit" their r three wires 2 power for each light & 1 ground make sure both lights r grounded

I too would share the ground, and leave one conductor and plug/socket pole free as a spare. But given that it's wired already, I'd start by checking the DC resistance across both units, and if it's very high on the deck light, try tying the two grounds together and measure again. If still high, it's on the + conductor. If not, it's the ground. At least the OP will know where the problem is, and can take action from there.

I,m using the 4th pin for my LED spreader lights

J