Part Identification-Chargin Issue

[Tonys113]

Would someone please identify the part shown here. It is bolted with the Voltage Regulator to the passenger side fender.
I had not driven my 69 280SL for about a week when yesterday ready to go for a leisurely drive around town it wouldn't start. Dead Battery.
First time ever. After a jump start I connected a volt meter to the battery and there was only 12.4VDC with the car running. I left a battery Charger on overnight  and the car started with no problem but the best the alternator will put out is 12.6VDC at 2000rpm. The belt is tight, the connection are good. The alternator appears to be a replacement as it looks too good to be OEM, though I cannot read any numbers on it readily. I took out the voltage regulator and look to have been very warm but once the cover was removed everything look to be in order, however the is continuity between terminal D1 and D2 and continuity between DF and the Case.

Any suggestions
Thanks

Tony

[Naj ✝︎]

Hi, Tony,

My guess is it is a solid state voltage regulator. Is the 'other regulator connected as well? It would have a similar 3 blade wire connection.

Naj

[al_lieffring]

the piece in the photo is part of the optional radio noise supression package. This was usually fitted in cars with a shortwave band radio. It is installed in addition to the voltage regulator, not as a replacement.

[Tonys113]

Thank you Al and Naj,
Noise suppressor would make perfect sense as it was actully connected to itself. Another words not connected to the voltage regulator. I did notice that it had the same connector on the end as the harness to the regulator but is was not being used.

Would a faulty regulator limit the charging voltage ?

Tony

[Raymond]

The regulator is just an on/off relay.  The alternator should be putting out well over 13 volts. 

[hands_aus]

I thought the regulator was incorporated into the alternator on the 280SL.
The 230 and 250SLs have separate regulators mounted on the inside mudguard.