W203 2002 wiring diagram for indicators

[docklander]

Any clues where I can find this or does anyone have it?

A Google search has so far not helped me.

 

[Ted]

Can’t help with a schematic but iirc the colours are black/green for one side and black/white for the other.
What is the problem you are having?

 

[docklander]

Can’t help with a schematic but iirc the colours are black/green for one side and black/white for the other.
What is the problem you are having?

I am preparing a track car and believe I have removed the wiring for the indicators and possibly fuel gauge by mistake!

I was really careful not to remove anything other than useless stuff; any idea where the cables run from? Thanks!

 

[Ted]

pretty sure they would come from the rear SAM.

AutoHex diagnostic scanner and information about Mercedes benz 203 Rear SAM system

www.micro-tronik.com

 

[docklander]

That is helpful. I do remember a thick-ish cable running down the side of the car, front to rear, black with a green stripe and one with a white stripe; do you think that was it?

 

[Ted]

At a guess, yes that sounds like them.
i wouldn’t expect them to be thick though.

 

[Stratman]

One Drive link to wiring diagram:- W203 indicators_20210605_0001.pdf


It's a PDF so hopefully you can expand the relevant bits.

At least it was a PDF when I uploaded it, who knows what mangling M$ have done to it.

 

[docklander]

One Drive link to wiring diagram:- W203 indicators_20210605_0001.pdf


It's a PDF so hopefully you can expand they relevant bits.

At least it was a PDF when I uploaded it, who knows what mangling M$ have done to it.

So it says on that PDF that it is a "typical" wiring diagram? Does that mean typical for W203?

Thanks

 

[Stratman]

It came from my Haynes pre-facelift W203 manual, sadly there was no diagram for the fuel sender. By 'typical' I think they mean some components depend on options ordered when purchased. I can't imagine the indicator circuits will be different between models and options.

 

[docklander]

It came from my Haynes pre-facelift W203 manual, sadly there was no diagram for the fuel sender. By 'typical' I think they mean some components depend on options ordered when purchased. I can't imagine the indicator circuits will be different between models and options.

Thanks.

Having checked, my brake lights and fog lights are also not working. At a guess, I think I may have taken out an earth. I have seen the small black/green and black/white cables and they seem unchanged. I have not messed with any cabling from the stalk, so that is why I am thinking the earth.

BUT, still a bit stuck about where I go from here;

 

[Ted]

Unlikely to be an earth. The current will flow through the bulb and return through a common path such as the sidelights and from there to the other side or the front of the car.
A bit hard to explain in writing but I’m sure you’ve seen the result of a bad earth where the current is returning through (say) the brake lights, the brakes are applied and the sidelight will go out as it no longer has a return path.
Fwiw the earth wire is brown.
Time to get a testlight - Halfords sell them and start checking out the circuit(s).

 

[docklander]

Picked up the one from Halfords for a tenner. My main concern is that I have actually taken out a wire that is essential. A table or diagram showing what the cables coming out the SAM are for their colours would be so helpful.

 

[docklander]

I ordered the repair manual from ebay for another tenner and will try and spend some time on the old girl this weekend...

 

[markmifsud]

GRN/BLK and WHT/BLK

 

[docklander]

Thanks, I wonder why the brake lights, fuel gauge and indicators all went out at the same time?

 

[Ted]

Not trying to be pedantic but that is black/green and black/white.
First colour is the ‘main’ colour which can also help to identify the source supply - black being ignition controlled, the second is the tracer.
You see this a lot more on the old Lucas type wiring schemes.

 

[markmifsud]

First colour is the ‘main’ colour which can also help to identify the source supply - black being ignition controlled, the second is the tracer.
You see this a lot more on the old Lucas type wiring schemes.

Hi Ted, are you saying that the reverse lamps are not ignition controlled, being Grey+stripe?

 

[Ted]

Hi Mark, from memory grey is the main colour for sidelights - e.g. grey/black for left side and grey/red for right side.
this is a general rule and doesn’t always follow through - brown is earth but canbus twisted pair are brown and brown/red.
UK colours were clearer
Main colours were
Brown permanent live
Purple fused permanent live
White ignition live
Green fused ignition live
Black earth
Blue Headlamp.
So as an example you would have a brown wire to the headlamp switch, the wire from there would be blue to the dip switch, then blue/white to main beam (and warning light) and blue/red to dip.
haven’t done this for 50 years and still fresh, but I can’t remember what I did yesterday!

 

[docklander]

I think what has happened is I have cut a wire that runs from the front to the rear SAM. All the wires running from the rear SAM to the rear lamp assemblies are intact and untouched. I assume there is a wire that runs from brake pedal sensor to the rear SAM and I am worried that may be cut?

 

[markmifsud]

S9/1 Brake Sensor