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Thread: 12v pool light system troubleshooting

  1. #1
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    12v pool light system troubleshooting

    I can't get my pool light to work. I have a 12v system. I pulled the light housing from the pool and onto the deck, opened it and measured the voltage in the socket. I got 13v (i guess that's acceptable). But I have 2 new out of the box lights and none work. If i get power to the housing, and my light bulbs are new, what can the problem be?

  2. #2
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    Re: 12v pool light system troubleshooting

    Ohm check the bulbs directly and through the wires.

    Scott
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  3. #3
    Mod Squad JohnT's Avatar
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    Re: 12v pool light system troubleshooting

    A bad connection will show full voltage with no load, but can't provide enough current to maintain the voltage when the bulb is connected. Try measuring the voltage across the bulb while it's in the socket or connected with clip leads.
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    Re: 12v pool light system troubleshooting

    Thanks for the replies. I don't think I understand Exactly what is it I'm supposed to check to figure if the problem is in a wire or in the transformer. Can you be more specific, what readings I'm looking for, etc,? I really appreciate it.

  5. #5
    Senior Member Ohm_Boy's Avatar
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    Re: 12v pool light system troubleshooting

    The trick is to take your voltage measurements with the transformer and bulb connected in the circuit.

    You'll want to measure the voltage at the transformer, and at the bulb itself with the power on and the bulb connected.

    -- If you have low/no voltage at the transformer, then the transformer or the main supply to it is bad.
    -- If you have good voltage at the transformer, and low voltage at the bulb, then the wiring between the two has a cut/bad connection somewhere.
    -- If you have good voltage at the bulb, and the bulb is not illuminated, then the bulb is bad.
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  6. #6
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    Re: 12v pool light system troubleshooting

    You can check resistance with the power disconnected at the deck box, aka junction box, where the line power meets the fixture's cord. A 10K+ ohm reading indicates a dead bulb. A reading of only a few ohms from there indicates a good bulb usually.

    With the line power and fixture cord separated in the deck box, you should see your 12VAC .

    It that is what you are finding, the question is then, did you get a 12V bulb or a 120V bulb.

    Scott
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  7. #7
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    Re: 12v pool light system troubleshooting

    Thanks for all the replies. I went to home depot and bought a light socket and connected the short wires directly to the transformer. It lit up the bulbs just fine. So just before i go buy a new light housing, let me know guys, this should pretty much be confirmation that the problem is in the wire fromm the junction box to the pool, right?

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    Re: 12v pool light system troubleshooting

    ...and by the way, do I have to drain the water from the pool to change the housing and wire?

  9. #9
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    Re: 12v pool light system troubleshooting

    Quote Originally Posted by floridian
    ...and by the way, do I have to drain the water from the pool to change the housing and wire?
    No.

    Your problem could be as simple as a loose connection. Is there a junction box for the light near the pool?
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  10. #10
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    Re: 12v pool light system troubleshooting

    The connection between the transformer and the pool light seems solid, tightly twisted wires. This connection is where I connected the small socket to test the lights.

  11. #11
    Senior Member Ohm_Boy's Avatar
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    Re: 12v pool light system troubleshooting

    Quote Originally Posted by floridian
    The connection between the transformer and the pool light seems solid, tightly twisted wires. This connection is where I connected the small socket to test the lights.
    Then it would seem that the circuitry between that connection point and the bulb is where the problem lies.
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