silly alternator help

s52e368 · Post by **s52e368** » Tue Apr 22, 2014 4:28 pm

i have a new alternator but no OE wires!

pulled the harness for a stand alone big m30 build.
the alt is a 3 wire. connections for (B , + , D )

any help on that?

i have the battery line connected but not sure on the spade connections or if this thing needs a housing ground ?

Mike W. · Post by **Mike W.** » Tue Apr 22, 2014 9:14 pm

This should help. + is for the capacitor, it helps prevent radio noise. D+ is field, or the small blue wire. Large red goes to B or Batt, and you may or may not need a seperate ground wire, most, but not all are rubber mounted. If it is rubber mounted you will need a ground just as large as the large red wire going to the battery, but you can just run it to the block inches away.

s52e368 · Post by **s52e368** » Tue Apr 22, 2014 10:59 pm

great thanks!! im pretty sure the blue is for the dash/warning light, no?
my new unit doesnt have a capacitor should it or can i use the old one?

Mike W. · Post by **Mike W.** » Wed Apr 23, 2014 10:29 pm

s52e368 wrote:great thanks!! im pretty sure the blue is for the dash/warning light, no?

Correct. The alternator won't start charging without it.

my new unit doesnt have a capacitor should it or can i use the old one?

You can reuse the old one, I don't think I've ever seen one go bad.

s52e368 · Post by **s52e368** » Sun May 04, 2014 2:34 pm

happen to know which pin the blue wire from alt goes to on fuse box connecter?

apparently i choose the wrong one as the alt isnt charging.

Mike W. · Post by **Mike W.** » Mon May 05, 2014 9:42 pm

s52e368 wrote:happen to know which pin the blue wire from alt goes to on fuse box connecter?

apparently i choose the wrong one as the alt isnt charging.

I don't have the manual at hand, but does the light come on when you hook things up? And you can always look inside the fusebox, it's unlikely they would change the color coding on the wire. Oh, that's with the battery disconnected.

s52e368 · Post by **s52e368** » Tue May 06, 2014 7:44 am

Mike W. wrote:
s52e368 wrote:happen to know which pin the blue wire from alt goes to on fuse box connecter?

apparently i choose the wrong one as the alt isnt charging.
I don't have the manual at hand, but does the light come on when you hook things up? And you can always look inside the fusebox, it's unlikely they would change the color coding on the wire. Oh, that's with the battery disconnected.

well the issue is I've pulled the engine harness and built a new one for the haltech I'm running. so I'm trying to figure out which pin is the charging pin on the fusebox engine connector.. the diagram i have states pin 8 on the diagnostic port, but pin 8 has continunty with 3 pins on the connector side with varying amounts of resistance. i used the one with zero resistance and its not charging..

Mike W. · Post by **Mike W.** » Tue May 06, 2014 11:43 pm

You would be looking for a wire that has 12V with the ignition on, but 0 with it off. But that hot to ground should only be about .2A since it's going thru a bulb. And new harness aside, it would appear you haven't cracked the fusebox yet? I'll look in a couple of days, I have long work days and get lazy afterwards.

s52e368 · Post by **s52e368** » Thu May 08, 2014 7:55 pm

well my bulb is intact but doesnt come on in the system...

yes i havent crack my fuse box open done everything else but not that! any pointers?

also need to figure out which of the 3 tach leds on the back of the cluster is an input

thanks man!

s52e368 · Post by **s52e368** » Sun May 11, 2014 6:40 am

whelp got the fuse box, and located the blue wire *from the diag connector claiming to go to my alt light...

though i found several other blue wires that are not connected but share continuity

s52e368 · Post by **s52e368** » Wed May 14, 2014 1:55 pm

s52e368 wrote:whelp got the fuse box, and located the blue wire *from the diag connector claiming to go to my alt light...

though i found several other blue wires that are not connected but share continuity

this didnt charge.

read somewhere else where someone connected D to the battery with bulb or fuse in line... this actually drained the battery completely .