On this page, you’ll find a short video outlining the common causes of a cigarette lighter/power point that won’t work.
This page is dedicated to helping you locate and fix the problem. Here you’ll find some mechanics tips for diagnosing and you’ll also find links to tools that will help make the job a little easier.
The video above gives you a flavor of what your problem likely is and here I’ll share a few tips to help you find and fix them.
Checking a fact is a fact
I’m an ex-GM technician and GM taught me to first verify we have a problem. It’s best to start at the very beginning, assumption burn time like you wouldn’t believe. In the case of our power-point that doesn’t work, we should go ahead and verify that is indeed a fact.
- Problem-power points – I’ve found it’s more likely to be a faulty phone charger plug or cable that causes the issue. Trying the consumer in a different vehicle helps to quickly rule this one out.
- Ignition on? – some power-points require ignition in position two before they power up. You can check your driver’s manual for the correct power-point functions.
- More than one consumer – use more than one test consumer cable (phone charger cable etc) to test the vehicle’s power-point.
Low hanging fruit
With a fault verified, a time-pressured technician will usually move on to quickly check all the low-hanging fruit. That means checking all the easy-to-check stuff, some of these may be remote but as they don’t take a ton of time, they are a good time investment. Here’s the low hanging fruit list:
- Check socket debris – sweet wrapers etc jammed in the socket will prevent operation. Indeed the location of some power points promotes the collection of debris.
- Check for socket corrosion – power points employ metal contacts to create a circuitm. Mositure in the socket will eventually turn to corrosion. A spilt beverage or vehicle with a ton of interior moisture may result in socket corrosion.
- Check fuse – a faulty consumer or a consumer that pulls greater amps that the socket fuse rating allows will cause the fuse to blow. This is normal behaviour and is actually a good thing as it protects your power point wiring circuit from excessive amp draw.
Fuse rating may be found in your user manual in the fuses section. Fuses are marked with fuse size and are color-coded for ease.
With all the low-hanging fruit checked, it’s time to roll the sleeves and actually use some tools. The best tool for the job is a power probe, but a humble test light will work great too. Check for power and ground at the socket itself and if you find you’re missing one or the other, move to the fuse box and check power there.
I avoid stripping interior trim unless absolutely necessary. Stripping risks damaging delicate trim clips and usually takes a ton of time.
That said after you’ve checked and found no power it may well require trim removal to check for loose wiring or broken terminals. But just before going down that road I’d consult a wiring diagram to check routing etc.
Use a Power probe, Voltmeter, or a test light works great also.
Note: There’s a risk of a flat battery when troubleshooting with the ignition switched on (pos 2). To prevent this use a battery maintainer.
A Power probe is an excellent tool to have around. Great for testing circuits, relays, fuses, checking battery voltage, checking alternator output, checking the ground, volt drop testing. I’ve had a power probe forever and it’s still going strong. Picture links to Amazon.com.
This is a battery post and terminal cleaner, but we can use it to clean surface corrosion from the power-point. Note before placing the brush inside the power-point, remove the fuse first otherwise the wire brush will short out and blow the fuse. Picture links to Amazon.com.
Electrical contact cleaner is an auto electrician’s best friend. Fretting or micro corrosion commonly occurs in automotive wiring terminals. And as you know, modules are super sensitive to changes in resistance. Cleaning the terminals is very often all that is required to solve irritating intermittent gremlins. Picture links to Amazon.com.
The NOCO genius battery charger is what’s known as a smart charger also known as a battery maintainer or trickle charger. They are smart because they detect the battery state of charge and automatically turn it off and on as needed.
If you are troubleshooting with the ignition system on, it kills the battery especially higher-end vehicles, to prevent this we use a battery maintainer. Picture links to Amazon.com.
A head-mounted lamp is like having a third hand a real advantage when you are doing battle. This rechargeable LEd head-mounted lamp is conveniently sold and delivered by Amazon.com.
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.