generator light for my 1970 280 SL glows dimly when car is running, but stopped.

[Bob]

I noted that the generator light glowed red (dimly, not "bright red") whenever the car was in gear but not moving (as whenever I stopped at a light).   As soon as any acceleration was applied, however, the light went out.   In "park" the generator light doesn't go on.   I noted that the light dimly lit up when the car was put in "reverse".    The light never went on while I was moving or driving along.

The car seemed to function fine otherwise, and there was no problem starting it.    It did not stall or hiccup at any time, nor die.

Any ideas or suggestions to remedy this.

[Larry & Norma]

I guess the alternator is not turning fast enough under these conditions and therefore not charging, but is ok at higher rpm.
Could it be an issue with pulley sizes or simply a loose belt?

[ja17]

Hello,

Check the alternator belt first as mentioned.  The dim light could be a waning of alternator or regulator problems to come.  Take a voltage meter and check the voltage at the battery with the engine running.  It sould be around 13.5 to 14.25 on a good system. Next try it with the headlights on.

[rwmastel]

It could also be the constant speed solenoid(?).  Do a search on that.  It's a device that is supposed to be activated to keep the idle up when a load is put on the engine (put in gear on automatic trans, turn on A/C, etc.).

[Cees Klumper]

Rodd is back!!

[J. Huber]

Rodd is back!!

I noticed that too! Hey Rodd..

Hey Bob. Mine experiences the very same symptoms on occasion. Been doing it for years. I have had my alternator checked and my belt is fairly taut. I cannot say for sure the belt is "too loose" or "too tight" because I just use my finger and it has about a 3/8 or 1/2 inch play if I tug it? I agree it could be the result of the CSS -- not sure how to tell that. My CSS works and keeps up the idle but may be a bit worn out.

Mine shows the red light on initial start-up -- then goes away upon first throttle. Then it will re-appear sometimes at a stop light or when putting into gear. I notice it comes on dimly after a long hard run. Really don't blame it -- darn car is almost 50!

[ejboyd5]

Clean the connections where the wiring harness attaches to the alternator.

[al_lieffring]

On a 280sl with air conditioning, the alternator does not drive directly off the crank pulley, The A/C belts need to be checked for tightness too.

If you have checked everything under the hood and the light still comes on, check terminal 30 on the headlight switch. This it the main power bus for the electrical system. The wires can corrode and cause enough voltage dorp to make the alternator light to come on. Some times the terminal on the light switch will be charred and require replacement of the switch.

[simonadot]

hello, i just experienced this today and the car went dead while driving, as I turned the key and no battery what so ever??? doe s that mean i need a new alternator?? I assume I do , because the battery is one week old and it starts with a jump.. can it be some other issue.
does anyone know a good honest machanic that can work on a 250sl in the los angeles area???