w211 - found a spare wire - is it live?

[madeinengland]

I want to hardwire a road angel and tomtom in my W211 (2003 E class). I took off the cover for the fuses on the dash (offside) and there was a red wire floating around with a spade connector. Is this a switched live wire? does anyone know as it will save a lot of messing about if this is so.

 

[television]

I want to hardwire a road angel and tomtom in my W211 (2003 E class). I took off the cover for the fuses on the dash (offside) and there was a red wire floating around with a spade connector. Is this a switched live wire? does anyone know as it will save a lot of messing about if this is so.

You may not get an answer to this, put a meter on it to see if it is live

 

[madeinengland]

Could you tell me how to do this. I have a mutimeter but only used it for continuity testing.

 

[DougCLK320]

Could you tell me how to do this. I have a mutimeter but only used it for continuity testing.

err...
Switch your multimeter to DC 12v or the next highest voltage rating and connect the meter's red lead to your mystery lead and the meter's other lead to a suitable earth. If the needle (or digital display) moves, you've got power....
Doug

 

[jberks]

The electronics on a 211 are scary. Even if it's live now, doesn't mean that it will be live in 5 minutes. Things come on and go off almost randomly and get it wrong and you're in for lots of problems and cost. Tripple this if, as I suspect from your question, you're not too experienced with auto electrics.
Just wire into the back of the cig lighter/12v socket. Easy and safe.

 

[madeinengland]

Thanks for the replies, I'll give the mystery wire the test.

The reason I didn't want to to via the cig socket is due to the fact I don't want to tear half the car apart (and probably break something) just to route a few cables. Also I haven't the faintest idea how to get all the stuff out to get to the cig lighter. I have tried a search on here but there doesn't seem to be any posts on how to remove all this stuff.

 

[David Nock]

Thanks for the replies, I'll give the mystery wire the test.

The reason I didn't want to to via the cig socket is due to the fact I don't want to tear half the car apart (and probably break something) just to route a few cables. Also I haven't the faintest idea how to get all the stuff out to get to the cig lighter. I have tried a search on here but there doesn't seem to be any posts on how to remove all this stuff.

I don't know how feasible this is on your car but when I've done this kind of thing on older cars, I've found it quicker to route a separate feed from the battery and usually managed to find a way through the bulkhead. You MUST use an inline fuse at the battery terminals though. Plus the feed is permanently on and not through the ignition switch.
Perhaps this is a bad idea on modern Mercs? Someone will no doubt tell me if it's not advisable anymore.

 

[television]

Always the easiest place to take an all time live feed is from the headlamp switch

 

[madeinengland]

I would prefer the live to be switched on with the ignition rather than an "always on" feed. I will fit online fuses to both devices when I discover the live wire.

Thanks for the comments though !!

 

[shakeapaw]

Open the ash tray and pull up the gear lever cover plate with your fingers from the front,it can then be removed by moving it backwards.lift up ther cover plate so you have access to the wires underneath (w/s switch,parking sensors etc) and disconected these,next twist the black plastic locking nut half/3/4 off a turn under the gear lever and pull the whole unit off.there are now 2 torx screws,cant remember what size they are,undo these,and the ash tray/cig lighter slide out.Where do you intend the place the tomtom ?

 

[madeinengland]

Shakeapaw - Tom Tom on the far RHS of the windscreen ie in front of the driver, the RA I want to position in the bottom centre of the screen.