Red Charging Light

[mBdrvr]

Does the red charging light come on when the key is inserted (not turned) into the ignition switch?

[Jonny B]

I did not think so, but you made me look. I have a 1970 280 SL - inserting the car and nothing else, the red light does not come on. Turning it one click to the right, to unlock the steering wheel, no light. When turned  one more click, when you hear the fuel pump whine, the red light comes on.

[mBdrvr]

Thanks very much for looking.

My red charging light stays on when my key is out.

Some 280 SL's on BAT have pictures of the gauges with the key out and the light on. But most, I think, have the light out when the key is out.

I'm attaching a picture of one these cars on BAT.

I thought there might be a contact in the ignition switch that turned on the light when the key was in but the contact was stuck on my switch.

There's a short somewhere.

Thanks again,

Paul

[Pawel66]

I think it is a “door open” and “brake fluid level low” light on the picture.

[Cees Klumper]

That was my thought as well, but I couldn't check on my car.

[mBdrvr]

Thanks for the responses.

I'm attaching a picture of my gauges with the key out.

I don't have an owner's manual so I'm not sure which light indicates a discharge. The red light here is the top one of the three.

I disconnected the two connectors at the brake master cylinder. I don't get a light either connected or disconnected. I shorted the contacts on each connector and got no light so there is something else going on there. Note that the parking brake does not work perhaps PO disconnected something in that circuit. (All on the to do list).

The charging light goes off when the car is running and/or when the blue wire is disconnected at the regulator.

The BBB says one red light is the charging control light; the blue light (working) is for high beams and third is the parking brake and brake fluid light. Is the top light for the charging system? Is the brake light red as well? What's the correct order for the lights top down?

[Cees Klumper]

Does the light turn off when you close the driver's door?

[Pawel66]

You area Full Member, you have access to technical manual where in the section Electric System, Dashboard instruments it is described which light is which.

Bottom blue - high beam
Middle orange ( or red I suppose) - door open or brake fluid low
Top red - charging

Middle one will be lit without ignition when you open drivers door or any door, depending if you have switches in drivers only or both doors.

Middle one will be lit when brake fluid is low or when you bridge the pins in the master cylinder sockets but only with ignition on.


When you open door with ignition off and you have low brake fluid level or you bridge or short the pins in the master cylinder socket(s), your charging light will come on even without the key, fuel pump will start, etc. - you will power up the car as if she were with ignition on. This is a design issue of these cars.

Parking brake has no light whatsoever.


If you bridge the pins in the master cylinder socket without ignition, no light will switch on.


If you disconnect the blue wire from alternator, charging light will not be lit.


Assuming you have enough brake fluid and there is no short in that circuit, the normal operation is like this:

1. Doors closed, key out - nothing is lit.
2. Open door, key out - the middle light is lit
3. Close the door, nothing is lit
5. Key in, doors closed - still nothing lit
6. Key turned, doors closed - top red light is lit, you hear the fuel pump
8. Start the car, engine running, doors closed - top red light goes off, nothing is lit
9. Open door while engine is running - middle one lights up
10. Close door - it goes off
11. You are driving along, but you lost brake fluid - the middle light goes on, but when you turn off the engine, it goes off. Then when you open door to see what the hell happened, it will go on.

12. Probably the most important one: when you turn the key and hear the fuel pump, but the top light is off - you have no charging (can be burnt bulb or other failure in charging system).

And

When driving and the top light goes on - you just lost charging.

[BobH]

https://www.sl113.org/forums/index.php?topic=37987.msg278149#msg278149

Hello, in your other post about this problem the charging light seems to be behaving correctly, apart from when the key is not turned to position 1.  You don't mention whether the low fluid/door open light is on at any time.  If you had the low fluid level problem and the door was open, surely you would have the charge light and the fluid/open door light illuminated, as well as the pump running and the other possible side effects

You should not have a +ve supply at the charge lamp without the key in and turned, so i think this is where you need to investigate by removing the applicable fuses, one at a time, to establish where this +ve is coming from.  You say the charge light is off when the engine is running, or when you disconnect the wire from the regulator, which would be correct, as the alternator/regulator is supplying the -ve supply to the lamp when the engine isn't running, with the ignition in position 1

[mBdrvr]

Thanks for these replies.

The open door has no effect on any light but it seems that the middle light for brakes is not working at all. Could be a bulb. I'll check.

Thanks again.

Paul

[Pawel66]

Middle light is both for doors and brake fluid.