Wire Under Battery. What is it?

[avanwinkle]

I found this blue wire under battery that is not connected to anything on the tag end.  Need an Id for the wire and purpose if possible.  Thanks.[/img]

[clunker]

Hi - what is the model/year/etc of this SL? The wiring loom varies across types.

[avanwinkle]

It's a W113 1970.

[Benz Dr.]

That's the wiring connections for the capacitive discharge box.

[Pawel66]

Could you kindly put that in English?

[MikeSimon]

My Owner's Manual has a wiring diagram, which, I must say, is one of the most useless ones I have ever seen as it has no wire color indications.
Anyway, here it is. maybe it is the ground connection from the distributor - item 47.

[Garry]

Full Membership has its privileges.


There is a colour wire diagram in the restricted area of the Technical  Manual accessible by Full Members.


Garry
Membership Administrator

[mdsalemi]

Could you kindly put that in English?

I believe the 1970-1971 models featured a rather early design of a CD electronic ignition, by Bosch. CD=Capacitive Discharge.

https://en.wikipedia.org/wiki/Capacitor_discharge_ignition

Anyway, these featured a box that housed the electronics and this box was mounted underneath the battery, hence the wiring that Dan Caron Dr. Benz is referring to. Like all electronics, they don't last forever, and if they go bad they simply aren't worth replacing (good luck finding one and how old is that?) or repairing; you just change to the electronic ignition of your choice--Pertronix, Crane or a 123.

The Crane, by the way, also features a box, and it itself is a derivative of an older Lucas system I'm told. Anyway when I had my Crane, it too was mounted under the battery for a tidy look--invisible.

[Pawel66]

Thank you!