can a faulty light on a car cause a leak to earth and the battery to go flat?

Question

my car clonk out the other day at the petrol station,it would not turn over at all,i got it going again but when i switch the lights on the dashboard lights went very dim,today i have found the rear number plate light cluster full of water,i dried and cleaned up the socket and evrything now seems fine.The car seems to start ok and the dashboard is bright again.
can a faulty light cluster cause this problem or do i need to look elsewhere?

Answer 1

Yes, this could explain your problem. Normally the resistance of the light bulb limits the amount of current the lighting circuit uses. The wet light cluster was causing a short circuit, so that the lighting circuit was taking much more current than normal. I'm surprised you didn't blow the fuse on the lighting circuit but it depends how it's wired.

Answer 2

Dear Earth-

What you are talking about is called a parasitic draw. Yes this can cause the problem. One of the simple tests you can do your self is with a DVOM, (Digital Volt/Ohm Meter).

If you can locate the short to ground, then repair it and that should stop the draw. You might consider being observant of the celing light? Does it go out when the door is closed? Do you have a glove box light, does it go out when the switch is pressed? Do you have an illuminated radio/clock? Does this turn off when the key is turned off?

Water leaks against any of the electrical socket can cause a fault to ground too. Depending on their location they can even cause fuse trouble too, (blown fuses).

Have you recently had the battery replaced? Bad connection on the negative or positive terminals can cause problem. The same can be said for excessive corrosion on the terminals. If this is the case, clean and re-connect the battery cables.

If the battery is going dead often, you could possibly have a charging system problem too. Possibly a faulty generator/alternator.

These are all possibilities. Just keep in mind that chasing down a bad ground can be quite the task, especially if you dont know which circuit its in.

The easiest way to find that, is to check the fuse panel in your car with the DVOM. Which ever one shows a voltage draw while the car is not running is your suspitious one, and should be closely examined. You may need a wiring diagram to trace the circuit and locate the problem area.

If you feel the area is beyond your skills then you need to have a visit to your local shop. Be sure to include all of the details of your issue. This information is not only helpful to the technician, but can also provide clues as to where to start the search. Same is to be said, if you were able to locate the faulty circuit, but its beyond your abilities or tools to correct.

Good Luck!

Answer 3

Sure. If the socket is shorted, it can take the voltage to ground. If it was shorted, it should have blown the fuse. Corroded sockets can and have caused a lot of problems, especially in salty area of the country.

Answer 4

Yes water will drain your battery and it will drain it fast .