Alternator Pig tail

[ah53]

I'm mostly a lurker to the list but I'm hoping I can get some help.  The block on the back of my alternator cracked and feel to pieces.  I now have a new "pigtail" but am confused on how to wire it.  I can find the block attached to the engine but can find only 3 wires going to it.  I seem to lose the black wire coming from the three pronged plug and can not firgure out where it goes.  Thanks in advance for any help you can give.

Joe
'71 280SL Arabian gray

[jeffc280sl]

Hi Joe,

There are 3 wires that feed the connector are marked on the back of the alternator.  They are D+, DF and D-. The D+ and DF wires connect to terminals on the voltage regulator. Somewhere between the alt and vr a wire from the D+ terminal will go to feed the alternator charge light in the cluster guage.   The D- terminal on both the voltage regulator and alternator go to ground.

Jeff C.
1970 280SL 4-speed

[al_lieffring]

Does your alternator have an internal regulator? A black plastic block bolted on the back of the alt.
If so the black (df) wire that went from the external regulator by the right shock tower to the alternator is no longer needed.

113-042-10-014715
built 11 Jan 66
904/396 blue, Ivory Tex
condition- rust bucket

[ah53]

Yes I do have a voltage regulator.  I can trace the D+(red/blue-left hand wire)and the D-(brown-center wire)to the junction block fastened to the front of the engine by the oil pan. The DF(black left side wire) does not come out by the block.  Is this the wire that should be ground?
Thanks again.
               D+(red/blue)         DF(black)

                          D-(Brown)


Joe
280SL

[jeffc280sl]

Al brings up a good point.  I recently replaced my alternator with an integral voltage regulator type.  Let me know if you need help with this unit.

Jeff C.
1970 280SL 4-speed

[ah53]

Sorry after re reading my post I should have been clearer.  I have a separate voltage regulator in the right side fender but the alternator has a "black box" with FM216V?. There are some other numbers below but they a not easily read.  Is this the "black box"  Thanks.

Joe
'71 280SL