Cigarette Lighter Modification – a change that will remove power from plug when ignition is in off position.

I noticed on my girlfriends 2007 Cobalt LT that both cigarette lighter plugs appear to be live when the car’s ignition is in the off position. I’d like to change this as she left her aftermarket seat heater plugged in and killed the battery. Ideas?

What I’ve thought up so far:

Option 1: I noticed that heated seats are an OEM option for some Cobalts. Do you guys think I could tap into a possibly preexisting wiring harness where the OEM heated seats would plug in? If so, could I get advice on where to find it, how to tap into it, what tools/parts I’d have to use? I’d assume I could buy a plug at an auto parts store…

Option 2: do nothing and hope she remembers to unplug her seat heater every time. This option isn’t working too well as she now fears to use the heated seat, as she may forget to unplug it again. Its my christmas gift to her so I'd like her to use it...

Option 3: tap into another power source that shuts off when the ignition is in the off position. This may be challenging as I’d have to check that the wiring could handle the 150W load…

Option 4: Is there a simple device that I can plug into the cigarette lighter that “knows” when the car is off and shuts off as well?

Other options? I’m a materials science engineer who got a “D” in electrical theory so I’d like to avoid doing any electrical work myself without quality instructions. I’ll probably find a local repair shop, a friend, or stereo shop…

 

Just get a relay and place it inline with the positive wire and run the trigger to a switched source on the fuse box such as sunroof.

 

yup thats the only good way to do it

 

turns out the gf has a warranty on the car for another 2 years that I don't want to void... I'd have to check with a local shop just to make 100% sure I don't void it...so you guys don't think there is a heated seat wiring harness near the stock seats?


voltage drop sensing device that sits in lighter plug,
I think there is a device out there that you can plug into the cigarette lighter, that'll since the reduction in voltage between when the car is off, and on, and shut off the plug accordingly. I'll look online...just not sure what keywords to use...

if I go and wire it myself:
I didn't see it at advance, auto zone, or best buy, but I did see the cigaratte lighter plug. I'm guessing since I don't have any tools I'll need the plug, wire crimper, one of those sticks that light up when wires are live, some wire..


thanks for the advice! I didn't really care for cobalts but the more I learn about them the more I like them. As soon as her warranty is over I may bolt on a turbo, or not b/c its an a/t

 

Magnuson Moss Warranty Act-If they cant prove that the work you did caused the problem then they must cover it. I had this issues with my 07ls when I installed my red/blue lights and siren for the fire dept. The dealer didnt want to cover an issue with the alternator. I have a printed copy I kept in the car. They got all huffy when I threw it down on thier counter but it got them to fix it anyway. Just a little food for though.