quick alternator question

mattduncan · 07-29-2005, 05:47 PM

Im in the middle of putting my 82' SC engine back together and have an alternator wiring question (I didn't take pictures

).

As looking at the back of the alternator, the big red wire connects to 5 o'clock. Which one does the blue wire connect too? 7 or 11 o'clock?

Oh ya, i've checked the wiring diagram and unfortunatly the alternator is labled D- in the middle of the plate so I can't tell if which terminal is D- and which is D+.

Thanks

Matt

mattduncan · 08-11-2005, 12:35 PM

OK, I really do need help. I have the engine running but I must have hooked it up wrong. There is no voltage at the battery (charging voltage).

PLEASSSSSEEE Help... I've checked everywhere with no luck. I have to go racing soon and need to get it fixed!!

mtelliott · 08-11-2005, 02:00 PM

If I was home right now, I could tell you quickly. I have my alternator out and it's marked where each wire goes. I'll try and respond this evening.

Michael

mattduncan · 08-11-2005, 02:32 PM

"If I was home right now, I could tell you quickly. I have my alternator out and it's marked where each wire goes. I'll try and respond this evening."

Michael,

Thank you, thank you and thanks again...this is driving me batty..

911mot · 911mot's Garage

Does the ignition light come on?
If not, check the bulb before pulling the alternator. A blown bulb stops the alternator from charging.

If it comes on and goes out when started but still doesn't charge at the battery, check you've got a good clean connection to the starter motor solenoid feed terminal. There should be two thick wires, one carries charge from the alternator, the other main feed straight from the battery, hence the need for a good connection.

If the light comes on and doesn't go out on starting (or glows dimly) you need to check that (1) the blue wire is on the correct terminal of the alternator and (2) that the connection in the multiplug that hooks it back into the cars wiring loom is good.

911mot · 911mot's Garage

Also aren't the D- and D+ terminals different sizes...so the blue wire would only fit the right (correct) one?

mattduncan · 08-11-2005, 03:08 PM

Quote:

Originally posted by 911mot
Also aren't the D- and D+ terminals different sizes...so the blue wire would only fit the right (correct) one?

Thats what I thought also when I took it apart..."Won't be hard to remember which one, it only fits on one.". But for some #%^@# reason, I have it wrong and don't want to tear it down again after I fix it this time....

The light is always on. Good bulb. Ignition in any "on" position or the engine running. Thanks for that input though, I didn't know that about the bulb. That could drive a person crazy trying to troublshoot a different problem.

Rick V · 08-11-2005, 03:12 PM

acording to my bentley manual you should have 3 wires on the alt.
1Big red puppy to b+
1 blue wire to d+which goes to the alt warning light and the d+ side of the regulator(if externaly regulated)1 brown wire to the d- this goes to the eletrical componants (and the d- side of the regulator if external)
It APEARES that the lug you quest is at 7 oclock
good luck and happy racing

jdowty3 · jdowty3's Garage

You probably switched the the 2 wires that go to the regular size terminal studs. I did the same thing when I put my motor back together last spring.

mattduncan · 08-11-2005, 03:30 PM

Quote:

Originally posted by Rick V
acording to my bentley manual you should have 3 wires on the alt.
1Big red puppy to b+
1 blue wire to d+which goes to the alt warning light and the d+ side of the regulator(if externaly regulated)1 brown wire to the d- this goes to the eletrical componants (and the d- side of the regulator if external)
It APEARES that the lug you quest is at 7 oclock
good luck and happy racing

I have the bently also, and studied it till I'm brain dead. My problem is I don't have a D+ and D-1 stamped on the back, just D-1 right in the middle. Same with the B side. So I don't know if it's refering to the top or bottom post.

Rick V · 08-11-2005, 03:38 PM

can you start the car? If so you should have B+ on the d+ lug and a nothing on the other lug. The one producing B+ is the one you need. the other lug should be a ground or D-. Use a dvom and not a test light

mattduncan · 08-11-2005, 04:10 PM

Quote:

Originally posted by Rick V
can you start the car? If so you should have B+ on the d+ lug and a nothing on the other lug. The one producing B+ is the one you need. the other lug should be a ground or D-. Use a dvom and not a test light

Can you explain that in stupid terms? I don't get it... What is a dvom? What does "producing B+" mean? Does it mean possitive current?

Jim Sims · 08-11-2005, 04:15 PM

Need help installing alternator

Rick V · 08-11-2005, 04:52 PM

Ok dvom is a digital volt ohm meter. I recomend the use of this because you will get exact volt readings. New test lights will light up with as little as 2 volts. they are designed to give positive or neg. reagings only they don't convey voltage.
B+= batt. voltage positive B-=bettery voltage neg.
D+ or D- is switched or regulated voltage. it is used to control something like a light or regulator as in your case. it will supply the info the car needs to charge the batt(B+) and run the car.

jdowty3 · jdowty3's Garage

The large red wire and the normal brown wire connect to the terminal by the regulator. The blue wire goes to the other normal size terminal stud opposite the regulator.