[W126 Coupe] Electrical Problem - bad ground?

[Dawid Loubser]

Hi All,

My SEC started developing a subtle but strange problem a couple of  
days ago (it may have co-incided with
the attempted theft of my vehicle two weeks ago, but let's not go  
there - suffice it to say that I live in
South Africa, crime capital of the crime continent of the world).

When I step on the brake pedal, the headlights and interior lights  
dim ever so slightly. Even when the turn signal
is activated, all lights go slightly dimmer in tune with it. This is  
a subtle problem, but it worries me.

My car starts fine, every time (fairly new battery) and the low  
voltage warning light in the car does not light
up. What could the problem be? I was thinking of taking the car to an  
auto electrician, but I'd first of all
give it a go myself if you have some insight for me. I can't imagine  
this being an alternator problem, as
then my battery would be running down - but for more than a week like  
this, I have not had any problems
starting my car.

thank you,
Dawid