'68 250SL why does the red light stay on?

[jharkin]

is it a trouble indicator?
i know it comes on when the door is
opened, thought it went out when door closed

[Garry]

If it is not going out when you shut the door then it is possible the float in the Brake reservoir has a pin hole in it and sunk to the bottom of the reservoir or you are low on brake fluid.


Garry

[mauro12]

I realized that my light doesn’t not work when the door are opened or closed. I see the red light only when I turn on the car and fuel pump is activated. Do you know why ?

[Pawel66]

Mauro, which light are we talking about?

The door opening light and the brakes fluid light is, actually, orange. It lights up and goes out as you open or close the doors, or when you have brakes fluid level low (or e.g. pin hole in the float).

The red light there is the light showing ignition is on and to indicate no charging of battery.

It lights up when you turn the ignition key to the second position (first is accessory, then the second is ignition, the third is starter). Ignition starts powering of the fuel pump, that is why you hear it.
It should go out when you start the engine. If it does not go out when engine starts or if it lights up during engine running - it means you have no battery charging.

Which red light we are talking about and when exactly is it lit or not lit.

[mauro12]

I’m talking about the light that should appear when you open the door. In my car this light doesn’t work. Or maybe in the 250sl was not supposed to be active , I don’t know. The only red light that I see is when I turn on the ignition and disappear shortly after ( when the engine starts).

[mauro12]

Another thing that is strange is that in my car. ( ITALIAN version) the function of high beams flash light is not active . If I want to give signal to someone ( to overtake for example ) , I have to use the switch button near the clutch . If I pull the lever nothing happen. Maybe some wires are disconnected

[Pawel66]

Mauro,

1. The operation of the door switches that switch on and off the courtesy light under dash is well described in our Technical Manual. I am not sure if this was installed for all W113, but if you have door switches it should be there, I think.

https://www.sl113.org/wiki/Brake/LowFluidWarningLight

Is your courtesy light working? There are 3 positions: zero, door operated light, on. If on position works, and door operated not, you need to work on door switch to courtesy light power supply (double wire in the connector at the lamp) and switches themselves and power supply to those switches (they do not provide ground!). If the courtesy lamp does not work at all, check the bulb.

Is the instrument cluster control bulb ok? Check it by shorting the two wires in the plug connected to brake fluid cap while ignition is on. The bulb in the instrument cluster should light up.

2. As for headlight signal - I only know that American cars do not have that. Yours is Italian, so maybe it was somehow disconnected. There are posts on how to activate this function on American cars.

[mauro12]

The light under the dash is working when you open and close the doors.
The red light ( low brake fluid) that is supposed to be on when the door are open
Is not working.
The same thing with high beam
Flash light. I think is quite difficult to connect I read.  I’m scared to play around with the wire diagram. The most useful thing would be to activate the flash light

[Pawel66]

Have you checked if the orange light goes on when it gets the signal of low brake fluid level, i.e. with ignition on, when you short the two wires in the connector at the brake fluid reservoir cap? Or when you unscrew and lift the cap so that the float goes down as if the fluid level was low, also with ignition on? This is to check the bulb in the instrument cluster.

[mauro12]

I’ve never had any problem regarding low brake fluid luckily. I read that in case of low brake fluid, when you open the door you hear the fuel pump running, quite bizarre. The orange light in the dash doesn’t appear when I open or close the door.
The light under the dash is working (3 position light) .

[Pawel66]

I suggest you  do the instrument cluster bulb check. Unscrew the brake fluid reservoir cap and pull it out so that the float goes all the way down. Or short the two wires in the connector at the cap. With ignition on the orange light (same as the one for the doors opening) should light up if the bulb is good. Does it light up?

[mauro12]

I have a question . This orange light ( door indication light) should supposed to be on with the ignition on too?
In other words, if I open the door and the engine key is not connected, should I see the orange light on the dash or not?

[Pawel66]

This orange light should be:
- on when a door is opened, regardless of the ignition key position or presence; it is powered at all times
- on, only when ignition is on when brake fluid level is low

[mauro12]

Thank you for the explanation. So I’m sure that there is some short or maybe the bulb is not working .