What would cause the cigarette lighter to show 1/2 voltage?

[Martinjmpr]

Weird electrical problem, so looking for some input from the group.

Vehicle is my 2004 Suburban 1500, 4x4, 5.3 with a dual battery setup.

The truck has (from the factory) 2 12v outlets on the dash that are on separate circuits. The one on the left is for the cigarette lighter (remember those?) and the one on the right is just a 12v power outlet. They run to two different fuses, I think the cig outlet is a 10a and the power outlet is 15a.

Normally I use the power outlet (on the right) for my GPS and the cig outlet (left) to charge my phone. But a couple of weeks ago I noticed it wasn't charging. My first thought, of course, was "fuse." So I went and pulled the fuse, it was fine.

Then I stuck my little 12v plug-in volt meter and got a very curious result:



By comparison, this is the display when plugged into the "normal" operating 12v outlet on the right:



So to the electrical gurus here, what could cause this? As I said, the fuse looks fine (I even swapped in a known-good 10a fuse just to be sure.) If it was getting ZERO power I could understand that it could be a broken wire or a defective plug. But what would cause it to show "half power?"

Any ideas? Anyone else have anything similar happen?

This outlet was working fine until a couple of weeks ago. And I don't smoke so I don't ever use the cigarette lighter (I'm not even sure I still have it.)

Thanks in advance!

 

[DaveInDenver]

If you checked and replaced the fuse I'd suspect a connector has probably come loose on the back of the outlet or you have a wire that's broken in the harness somewhere. Could also be the outlet itself, maybe the stamped guts have fatigued and aren't making solid contact with the cigarette plug anymore. They are not exactly robust construction.

I have a similar set up on my Taco, one side is a power outlet the other a cigarette plug. Some plugs fit better than others and sometimes turning a quarter turn makes a nonfunctioning one work again.

Look inside, you'll see what I mean about how OEM outlets are made in the cheapest possible way.

 

[dwh]

Yea, my first thought is dodgy socket. Second is dodgy connections to the socket.

Though I do admit...never seen exactly that prob before...

 

[sancap]

Corrosion.

 

[RoyJ]

Did you check the voltage at the fuse? If it's 12V there, then there must be a bad connection down the circuit to the socket.

Though if resistance is so bad that a voltmeter is showing 6V, it's probably incapable of any current output.

 

[rayra]

Corrosion, faulty connection in the circuit, poor ground. one of those things is causing the undervolt