# **E46 DYI: How to make Cigarette Lighter turn ON/OFF with Accessories in 5 MINS!**



## MRjayr (Dec 13, 2010)

This mod is regarding the annoying issue of having a constant power source running to the cigarette lighter. If like me you have accesories such as GPS or an IPOD transmitter in it, it can be very annoying to be constantly plugging your items in and out to save the battery going flat. So today i finally got the time to do something about it! :excited:

Ok this mod is super easy and took me approx 5 minutes to do!

First you'll have to remove FUSE# 7 (Orange) for the Radio and Fuse# 47 (Blue) for the cigarette lighter
In this picture the fuses have already been pulled out. Each pin for the fuse has polarity.

Top is NEGATIVE (WHITE) & bottom is POSITVE (RED)



What were going to do is join the Negative from Fuse# 7 and join it with the Negative with fuse# 47.

But before we do were going to have to remove the fuse filament in fuse #47 OR just use a blown fuse. 


Then with a strip of wire preferably one with a fuse doesnt really matter we'll join the negative pole of fuse 7 to Negative pole of 47 with the use of a soldering gun.
I would really refrain from just wrapping the wire around the pole incase a strip of the wire comes lose and makes contact with the opposite pole.



Finally put back the fuses making sure that the poles with the soldered wire goes to the pin facing up circled in BLUE.



And thats all folks! 
Your cigarette lighter will now turn on and off with the switch of the accessories position.

ENJOY! 
Jay


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## TerraPhantm (Nov 22, 2004)

Is this really necessary? I was under the impression that the cigarette lighter gets turned off within about 15 minutes after locking the doors (like the trunk lights and whatnot). I know I leave my iPod plugged in all the time without issue


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## ShayMac8688 (Apr 7, 2011)

Yeah, my phone actually charges through the cig lighter when my car is off. 

Sent from my Droid using Bimmer App


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## nemesus (Sep 21, 2011)

I've been looking for something like this for ages now - really glad I came across this thread 

Just a question (I'm no electronic fundi) - Is this safe? 

Reason I am asking this - from what I can see is that the cigarette lighter will now run of the radio's 5A fuse instead of the 20A fuse? Unless the wire contains a 20A fuse in the fuse holder?

Is the circuitry on the fuse panel really split in to positive and negative? I would have thought every thing is grounded, and to power something the positive feed needs to be completed - So I would rather think the fuse panel is all positive terminals, and if the fuse blows (for example) the positive feed is broken thus causing the specific device to go off. If this is the case, this led me to think what kind of cabling (thickness) is running on the positive of the radio fuse circuitry? Because the positive (and negative) wires of the cigarette lighter is much thicker than any of the other wires because of the extra load it is capable of carrying...

I reaaaaalllly want to do this mod, trust me - Just a bit concerned about my above thoughts... Don't want to cause any short, or more important, long term damage to any of the electronics or it's wiring...

Any comments / ideas will be appreciated!! :thumbup:

Cheers!


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## GoForthFast (Jul 8, 2004)

nemesus said:


> I've been looking for something like this for ages now - really glad I came across this thread
> 
> Just a question (I'm no electronic fundi) - Is this safe?
> 
> ...


I normally would not butt in, but because you asked, I'll address my response to you rather than the others who want to do this mod.
You are correct, there is no positive and negative side to the fuses per se. There is the positive side and the load side which feeds anything that each fuse supplies with power. What this mod suggests you do is remove the fuse which normally supplies the cigarette lighter with power all the time. Then you just 'borrow' the feed off the switched radio fuse to feed the cigarette lighter socket. Thus you now have "switched power" over at the lighter socket.
The downside is you are now feeding the radio AND the cigarette lighter all from the same small 5 amp fuse. Theoretically this is not cause for great concern because if you overload this new configuration, you should merely blow the 5A fuse. I just hate to see a circuit designed with less than conservative safety in mind. Granted hardly anyone uses a cigarette ligher any more. (I've misplaced mine years ago) So you should be OK if you only use the radio along with normally low current drawing accessories such as a gps or ipod. But I do use a refrigerator, so this would not work in my situation. Each owner has to the the judge of his own applications. Explore the possibility of selling a car modified like this to a non-DIY type on your own time. It would be irresponsible in my mind.
And then there is one more aspect to this mod that I have an issue with. If I were to do this and want to feel good about the mod, I'd get to the back of the fuse block and bridge the two load sides of the fuse with a proper solder job and heat-shrinkable tubing. I would not solder to a blown fuse spade terminal to make the connection. I like my mods to be as close to factory solid as I can make them.
Notes: DO NOT consider increasing the value of the 5A fuse! It is fed from wiring rated only for 5A. You would create an unsafe situation.
It is virtually worthless to add the additional cartridge fuse in the bridge line. In effect you have put two fuses in series with each other. Not a conventional method of fusing.


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## Kimaanja (Mar 4, 2012)

By the way, your steering wheel is on the wrong side of the car


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## Freakusaurus (Feb 7, 2013)

I know I'm a little late to the party here, but I just came across this thread while looking for my own problem.. Funny is I was just googling a random search on ANY car and it brought me here and my problem happens to be with a BMW.. ANYWAY... I was hooking my radar detector into the lighter and of course that meant it never turned off... NO people, it does not turn off after so long or if you lock the doors in some mannor... it stays on.. ALWAYS.. What I ended up doing was hard wiring it into the fuse block with an add a circuit thingy from autozone.. bout $5.. The TOP row of fuses are switched on & off with the car.. the BOTTEM row of fuses is always on... SO my next step which may also help some of you is.. since I don't smoke I will be adding my own power ports (12V accessory plugs, USB plugs, etc.) in the car.. likely either in the front ash tray or in the one for the backseat attached to the center console... and as long as you wire it to the TOP row of fuses, it will turn off with the car.


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## Jennygirl (Nov 20, 2013)

I have the opposite problem need 1 of my 2 cig lighter outlets to stay on when car is off 
Thanks


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## badvlvo (Mar 26, 2009)

I like mine on all the time. Charging the phone while away from the car when I am traveling is great.


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## BrownGhost (May 16, 2017)

MRjayr said:


> This mod is regarding the annoying issue of having a constant power source running to the cigarette lighter. If like me you have accesories such as GPS or an IPOD transmitter in it, it can be very annoying to be constantly plugging your items in and out to save the battery going flat. So today i finally got the time to do something about it! :excited:
> 
> Ok this mod is super easy and took me approx 5 minutes to do!
> 
> ...


Great post, but all the images are not working 
Can you re-upload them?


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## MPW1 (Jun 18, 2016)

Old post yes but thanks worked a treat, I never knew this until I wired my scanner in and then it would turn off when I keyed off 
This is what I done









Sent from my iPhone using Bimmerfest mobile app


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## MRjayr (Dec 13, 2010)

Wow glad this diy is still helping out


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## MPW1 (Jun 18, 2016)

MRjayr said:


> Wow glad this diy is still helping out


Yes mate thanks a lot
It wasn't until I connected my scanner that I found out it was live all the time 
Done a search and your thread came up 
Thanks again mate 

Sent from my iPhone using Bimmerfest mobile app


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## gumper (Dec 30, 2020)

Hi
Just stumbled upon your old threat here and wish to do the same as I hate having to unplug my aftermarket dash cam every time. The pictures in your thread however do not seem to be there and as such I am worried about fooling around with my fuse box without seeing the pictures of exactly what you have done.



MRjayr said:


> This mod is regarding the annoying issue of having a constant power source running to the cigarette lighter. If like me you have accesories such as GPS or an IPOD transmitter in it, it can be very annoying to be constantly plugging your items in and out to save the battery going flat. So today i finally got the time to do something about it! :excited:
> 
> Ok this mod is super easy and took me approx 5 minutes to do!
> 
> ...


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