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Why Car 12 Volt Cigarette Socket Doesn’t Work

By on September 27, 2016










Was planning to use the cigarette socket to power up a brand new car dashboard video recording (DVR). Unfortunately, the DVR does not turn and initial suspect was the DVR itself is not working. Tested the DVR in another car and works like charm.

Decided to use a multimeter to test on the voltage output and the output was 12 volt which is correct. Later on I removed the whole center console unit to enable the cigarette socket to be slide out. Reprobe on the value and its 12 volt! And wiring connections is good to the socket.





But still does not power up any other devices also. I test it with a 12 volt light bulb and it does not light up at all.


Then, I disconnect wiring and go for offline troubleshooting on the socket itself after knowing the supply is 12 volt but does not light up through the socket. Testing the resistance between the socket to the wiring tip is not completely shorted and resistance value around 2-10 ohms were present. This is probably contact resistance which cause drop in voltage during load or device is plugged in. repair-car-12-volt-jack

I dismantle the socket from the plastic housing fix-car-12-volt-jack

After dismantling I cleaned all metal contacts with contact cleaner. Socket contact surface to the rear seems good at 0.52 ohms. The +12 volt wire are plug into metal plate (2nd from left) and are tighten with nuts to the socket.


After that putting the whole socket back to the plastic housing, it seems the resistance reading are back to normal at 0.55 ohms.


And putting it back to the car’s wiring, the light bulb light up and socket is good here. Therefore, don’t’ be fooled by having 12 volt but with resistance (poor contact), a simple 12 volt will have a dropout and will fail to power up gadgets. In conclusion, although it looks primitive and amateur way of checking using a 12 volt bulb but still it is a good way to verify the electric circuitry is going well all the way. I came across a lot of car mechanics will use light bulb instead of voltmeter or multimeter upon verifying electric wiring in the car. Probably light bulb light up and brightness will provide a good indication of whether the wiring has a bad contact.



YH Wong is from Malaysia with a degree in Computer Engineering. Currently, work as a test engineer in semiconductor industry. Avid in troubleshooting & repairing electronic gadgets related.

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  1. Parasuraman

    September 27, 2016 at 10:26 am

    Good job! Nice trick of troubleshooting! Thanks for sharing!

  2. Albert van Bemmelen

    September 27, 2016 at 2:10 pm

    Thank you YH Wong. Opening and closing the Dashboard often is a harsh job in itself. Maybe the internal Cigarette Socket contact resistance deteriorated because of overuse by the Cigarette Lighter Plug which gets very hot instantly? Glad your DVR Cam device now works! I hope the unit also supports GPS.

  3. Yogesh Panchal

    September 27, 2016 at 2:53 pm

    YH Wong,

    Good work! Keep Sharing.
    thanks for sharing.

  4. Suranga Electronics Sri Lanka

    September 27, 2016 at 4:55 pm

    Mr, YH Wong.
    Good Repair Work.

  5. Mark

    September 27, 2016 at 6:14 pm

    Well done YH Wong,
    As you have shown, resistance and voltage checks are not enough - a voltage drop test must be done. This is the only true way to correctly diagnose a tricky resistance issue.

    • YH Wong

      October 1, 2016 at 5:07 pm

      Thanks Mark.
      The 12volt bulb will have load enough voltage drop to stimulate whether are there resistance hindering it. If it is good enough to light up a bulb , I'm pretty sure won't have problem powering up gps, usb chargers and etc.

      • Emile

        October 5, 2016 at 9:19 am

        Nice technique in trouble shooting. Good job. Keep on sharing.

  6. WONG

    September 28, 2016 at 11:13 am

    I also have a Waja automatic just like yours and having problem with the original CD player. Can you show me how to open the dash board to access the CD player ?

    I had tried to remove the gear knob and a screw which secure the centre console but not sure how to remove the center console. Do I just pull out the console ? I am afraid I may break something if I pull the console out by force. May be you can show me some photos on how to pull out the console ?

    • YH Wong

      September 28, 2016 at 6:31 pm

      Hi Wong, Yes there is only a screw(covered by the black rubber) above automatic gear. Just pull the plastic console out on both sides of the light grey plastic.

      • Wong Sieh King

        September 29, 2016 at 10:54 am

        HI Wong

        Thanks for fast response !

        Is there any precautions I should take when removing the console to prevent damage ?

        • YH Wong

          October 1, 2016 at 5:05 pm

          Sieh King,

          Not much.... Proton car plastics are easily detachable..for this part it is quite sturdy. So no worries... go ahead !

  7. Robert Calk

    September 30, 2016 at 4:41 pm

    Nice job, YH Wong. A simple little test light is a handy tool. Thanks for the article.

    • YH Wong

      October 1, 2016 at 5:08 pm

      Thanks Robert C. Yes simple yet handy.

  8. Humberto

    September 30, 2016 at 8:24 pm

    Good repair Sir.

  9. Gerald

    October 1, 2016 at 8:04 am

    Hi YH Wong,

    Thanks for sharing. Nice reminder to always "picture" that invisible internal resistance. The same when measuring batteries, the digital voltmeter doesn't tell you the whole true... Well done.


  10. Arthur

    October 20, 2016 at 5:03 am

    Hi YH Wong, Good point,thanks for sharing!


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