mystery box on regulator

[bikerpete]

Does anyone know the identity of the small box plugged into the voltage regulator (1970 911 T; see picture below)?

I'm having charging problems (warning light on regardless of rpms, 11.9 V at battery at 3-4000 rpm) in spite of alternator rebuild, new voltage regulator, new belt with correct tension and all wire connections clean and tight.

In tracing wire continuity through this mystery box noted (with power off):
1. Continuity from D- pole on regulator and through mystery box through brown wire to ground.

2. Continuity from D+ pole on regulator (red wire into mystery box) through to blue wires leaving mystery box

3. No continuity from DF pole on regulator (black wire) to black wire leaving mystery box (apparently to DF pole on alternator).

I can't find this box on the (Haynes) wiring diagrams so I have no idea what it is suppossed to do. Is the lack of continuity on the DF line through the box, with power off, normal? It seems that unless it makes contact when the power is on then the alternator cannot possibly do its job with the DF circuit to the regulator interrupted. I'm hesitant to mess with it with the power on since I don't know what it is.

Any help would be greatly appreciated!

Thanks, Pete

[john walker's workshop]

noise suppressor. it can be eliminated, with no apparent radio noise as a result, and can also cause a charging problem if it goes wacko. same plug shape for it and the regulator, so toss it.

[Early_S_Man]

Pete,

That is a post-1973 style RFI/EMI suppressor ... apparently retro-fitted along with the regulator by a previous owner or wrench! Your car did not originally have the plug-style regulator!

The suppressor can safely be removed and discarded ... as it is often the source of alternator problems, as you have found!