clock only works when engine running

[philip grobien]

Hi all,

A bit new to my 230sl and trying to work out why some things work and don't work. Any idea why the clock only works when engine running. Is this normal?

Philip

[enochbell]

Phillip,

It is very unusual for the clock to run only while engine on.  The original clock draws a tiny amount of current from the battery, and that energy is stored in a spring that drives the clock mechanism.  The spring is loaded by an electro magnetic servo every few minutes or so.  The draw is so small that it would not, imo, be possible to start your car with a battery that was low enough to be unable to drive the clock.  So...one of two things have happened.  Either someone replaced the movement with a modern movement that requires constant current and/or someone wired the original clock improperly so that it is only hot when ignition is on. 

g

[WRe]

Hi,
I would suppose that someone changed the permanent power (fuse 1) to switched power only when the ignition is on.
https://www.sl113.org/wiki/Electrical/Clock
...WRe

[Tyler S]

One more possibility is the clock mechanism is worn or the electric winding points are burnt/ poor contact. The engine vibration is just enough to overcome an issue and keep the clock running.

[BaronYoungman]

If the clock needs rebuilding Chicago Clock Company did a GREAT job with 2 different ones for me.
Bob

[philip grobien]

Thanks guys.

I think I will find out how its connected first and then go from there.

Philip

[thelews]

did you mean engine running on or ignition on.?  If ignition, then the problem is that you are connected to a switched source instead of an always hot source.