What does this socket do? (Photo included)

I removed the leather trim piece below the tach-speedo cluster, in my '83 400i auto, to deal with an ignition switch problem. This gave me a chance to see the socket that's in the attached photo. This is a factory piece. The bracket that holds it is obviously factory-installed, and it appears in the wiring schematic in the '82 Owner's Manual, which identifies it simply as "socket." The male connector that has the light blue-red wire attached to it, the other two male connectors that you see with nothing connected to them, and the two contacts you can see inside the clear plastic housing -- they look kind of like the jack on an electric guitar -- are all the same piece. The light blue-red wire, and a second light-blue red-stripe wire in the same connector, that you can barely see, are always hot. This makes the socket an always-on power takeoff point. But the socket has no ground. Whatever you plug into it would need to be connected to an external ground. I've never seen anything like this. What is it for?
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No, your OM schematic shows that the ground is provided by the socket assembly being attached to that metal tab on the chassis (which is ground). It's for the plug-in "trouble light" in your toolkit. This post:

http://www.ferrarichat.com/forum/141503684-post21.html

has a photo of a trouble light 40179202 (don't know if yours for a late 400i is exactly the same, but it will be similar if not identical).

 

Hi Steve. With the photos of the accessory plug adapters in the linked post, showing that the trouble light uses a prong sticking out from a concentric housing, this makes sense, that the socket's housing would be the ground. My car and its trouble light parted ways long ago. But I think I will get one of those BMW motorcycle cigarette lighter adapters. It would be handy to have this power source. It is also the case that those two extra male connectors are available for any low current "always on" electrical needs.

 

It's nice to know what this is for - I thought it was a courtesy light bulb holder with the bulb missing. At meant to ask if anyone knew where to get the bulb from.

Boy, would I have felt stupid mentioning that!

 

The plug for this is called a Merit plug, see here:
Jaycar Electronics - Search Results for merit plug

There are merit plug to cigarette lighter socket adaptors, which then allows you to use std accessories, eg GPS or USB adapter for phone charging.

M

 

Good info. I am just starting to look into hiding some 12v outlets to charge a phone and power radar detector. I could always use the merit plug for my heated motorcycle gloves!

 

Any U.S. source for a Merit to cig. lighter adapter?

 

I've done a search (google and ebay) in the UK and these all seen to come from upsidedown land. Usually RS Components supply stuff like this but no luck there either.

It's a simple job to wire in a standard 12v power outlet in the glovebox which I've already done in the 400 but I like the idea of utilising the standard power outlet.

Anyone got any idea if they're available in the UK ?

 

c est une prise pour brancher une lampe baladeuse