Cigarette lighter in trunk
I need your help
I want to retrofit cigarette lighter in trunk of my E350 CDI - 2009, because the european model not have such.The first thing that immediately occurred to me was to find out fuse of the existing cigarette lighter in rear SAM module,
to put a wire on it for positive and another wire on chasis for negative.. and these 2 wires to the new cigarette lighter plug.
I search for some fuse diagrams and found that fuse # 71 is for interior light and fron cigarette lighter.
My question is: is this idea good?
I am afraid that if there is consumption of the new cigarette lighter or I confuse something with these direct cables from the fuse,
the rear SAM module will not fall asleep (sleep mode) when car is turn off in parking or I will confuse the ECU in some way

Please share your knowledge and tell me how to put cigarette lighter in my trunk without interfering with the current car ECU/electronics.
Thanks in advice
Example how to get positive wire from fuse:

Chris
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ha! Ain’t that the truth. I have one too. 😂




ha! Ain’t that the truth. I have one too. 😂
What are you doing?
Where's my purse? {Kept in trunk}
Can I leave now?
Why are you taking pictures of the fuse box?
Where's your car?
Is something broken?
Did you put it all back together?
Did you move my seat back?
Love!
Last edited by pierrejoliat; Apr 26, 2022 at 12:42 PM.




Last edited by pierrejoliat; Apr 26, 2022 at 03:53 PM.




I don't qualify as a stereo installer (sic), but I have added supplemental wiring to the rear fuse box several times without problems. As pierrejoliat has noted, simply add a fuse/tap to the rear fuse box for power to the new outlet, and ground it back to the common ground in the fusebox.
It might be good to identify the normal fuse # location and voltage for a rear outlet (that I know you don't have) on the (generic) fuse chart and add the new fuse of the specified voltage to that slot. On my car, it's slot #72 for "rear socket". So, if your chart says #71 for rear socket, you should be ok to proceed with it, as it should be a switched power slot (on when the car is running only). HTH.
Last edited by DFWdude; Apr 29, 2022 at 12:03 PM.




I would run 20 amp fuse/wire for it as with potential compressor use, the 15 amp might blow when you restart compressor under load.
Another question is if you want the outlet ignition -controlled, or permanently on?
I would run 20 amp fuse/wire for it as with potential compressor use, the 15 amp might blow when you restart compressor under load.
Another question is if you want the outlet ignition -controlled, or permanently on?




F72 is Cargo area socket (X58/4) and is the only load on Relay G.
If you use F71 Front cigarette lighter with ashtray illumination (R3), that is from Relay B.
Relay B not only supply to F71, but also :
F37 Driver seat NECK-PRO head restraint solenoid (Y24/12)
F83 Circuit 15R connector sleeve (Z3/12)
or Navigation processor (N41/1) <<< China cars
or Emergency call system control unit (N123/4)
or Electronic Toll Collection control unit (A50/3) <<< JAPAN
NOT using F71, will save the relay B contact life for more important fuses it serves.
F72 is from Relay G and is after all for a Cargo area socket
Since F72 or F71 is relay operated and rear SAM logic is controlling it, it can be time-out ( OFF ) according to rear SAM strategy. I am not super familiar with rear SAM time out strategy per relay it controls.
Othe thing for sure, Relay B and G is from 30g circuit, which means they are controlled by K2 big relay at engine bay F32 PreFuse housing. In sleep mode of the car computer/s, K2 will disengage ( Sleep/OFF /Open Circuit).
However the time for K2 to sleep is very dynamic. If you made a drive for X minutes, K2 may take hours to sleep.
If your car is parked for a few days and you open the door and K2 wakes up, it can sleep again under 30 minutes.
Have fun............
Ok for now, but when i check with multimeter, there is no voltage with/without engine on
Here is how i check it:
So where i misstake?




You must read on the SUPPLY /SOURCE side.
See below :
Test your Tap-A-Fuse and make sure it is the same internal wiring route as below :
You do not need to put a suposedly original F72 fuse, keep it empty.
I am assuming your Tap-A-Fuse is the same internal wire routing as sample I speak of.
SUPPLY = SOURCE
Test it and let us know




While you are at the Rear SAM, I shall show you another neat trick.
01. Those fuses labeled with white tape and stated for its amperage, are spare fuses. So easy to keep it there.
02. Those spare fuses will occupy empty un-used fuse slot, which believe it or not, when you are in the dark and hard to read the black fuse number print on rear SAM,
or in a bad mood due to fuse blown while on the road, or not paying attention and whatever.......
there are times you actually plug in the correct new fuse into a wrong slot. This happens to even seasoned mechanics and they ended up loosing hours trying to track down lost voltage.
By having the white tape label on the spare fuse, you know that is a spare fuse and those fuse slots are not used in your car.
The green row is easy to remember, because two fuses starts from very left and 2nd one next to it. No empty spaces in between like White, Red and Yellow row.
Yes, I use blue tape and some plastic cut out to cover RELAYS I do not have and MAXI FUSE I do not have and any other empty fuse slot I hate seeing naked-empty.
Have fun.....




Relay G also serve Fuse 76, I missed that sorry Bro.
This is one problem with MB wiring diagram of Front and Rear SAM, both in 10 sheets. To find 1 fuse or relay, you must see all 10 sheets separately because they can be placed it in 2 or more pages/sheet......damn.
212.1 model I don't know what W212 model that is.
On my car a 212.065 , I have this F76 fuse and I believe it is for my rear entertainment system , 2 TVs at front seats backside and 1 DVD/CD player at the rear seat azz-cushion.
I have not tested F76 by removing it yet though.
This just to show that MB fuse list is not updated enough for my facelift E400 / W212.065
I don't really trust a 100% MB W212 Rear SAM fuse list, because sometime they may miss newer models , the facelift ones.
Please verify your Fuse 76




Your quest made me started my Rear SAM fuse + relay cataloging again... LOL.
I completed Front SAM long time ago but stop 1/4 way for Rear SAM. Its a lot of work and take days to create my own guide book for these SAMS.
NOTE : US cars get printed/custom fuse list. Do you get one for front and rear SAMs ? My market version : zero-NIL-nada such luxury....
But hey, MB needs that savings, I guess







I order some