Author Topic: Alternator Wiring Help  (Read 106 times)

Offline Rosebud

Alternator Wiring Help
« on: October 11, 2017, 08:16:05 PM »
Received my new alternator today w/ no wiring instructions. Anyone familiar with this setup? My original alternator has a (3) wire plug coming from my wiring loom; (1) large gauge brown wire, (1) small gauge brown wire w/ yellow stripe, (1) small gauge black wire (see pic 1).

My new alternator has a (2) wire plug with a black wire and a blue wire and (1) large copper screw terminal coming from the side of the alternator (see pic 2). What goes where? I'm not very handy with a multimeter, but I have one if needed. Thanks!
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

Offline MiniDave

Re: Alternator Wiring Help
« Reply #1 on: October 11, 2017, 09:56:02 PM »
What kind of alternator is it? Where did it come from?

Clearly the big terminal goes to the battery via the starter solenoid.
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline Rosebud

Re: Alternator Wiring Help
« Reply #2 on: October 11, 2017, 10:23:39 PM »
What kind of alternator is it? Where did it come from?

Clearly the big terminal goes to the battery via the starter solenoid.


It's a PowerLite RAC068 "Lucas type." http://www.powerlite-units.com/products/rac068/. Since my original post I've figured out that the two (2) brown wires from my loom attach to the large threaded terminal on the new alternator. My concern now is which wire do I connect to my car's warning light wire; the black wire or the blue wire on the new alternator. PowerLite's wiring diagram is of no use as they show a green wire and a yellow wire coming from the new alternator. One is an ignition wire, the other one is the warning light wire. But which is which?
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

Offline Rosebud

Re: Alternator Wiring Help
« Reply #3 on: October 13, 2017, 12:19:37 AM »
Turns out PowerLite supplies 2 different wiring color codes with this particular alternator. Their website includes links to both wiring diagrams, but the particular one I needed was somewhat hidden. A member on another forum clued me in. All is well. Thanks!
Rosebud
...the sled, not the flower
https://www.facebook.com/PoserMotorSports

Offline MiniDave

Re: Alternator Wiring Help
« Reply #4 on: October 13, 2017, 09:37:20 AM »
Cool, glad you got it sorted....so which wire went where?

How many amps does it put out? Why did you go with that one instead of the usual Lucas 45 amp that would have plugged right in?
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline velopackrat

Re: Alternator Wiring Help
« Reply #5 on: October 13, 2017, 12:36:57 PM »
I've been down this path too.  D. Lawson helped me sort mine.  The Denso type alternator often has a two wire T fitting on the back.  The top part of the "T" is usually coded SW of IG, meaning it goes to the ignition switch.  The bottom part of the "T" goes to the Speedo dash light, brown / yellow wire.  But don't use the other brown wire for the IG pole because it will always supply voltage, even when the car is off.  The battery will suffer this small drain which over several days means dead battery.  One way to source a switched wire without running one from the ignition switch is, make a pigtail from coil positive to this IG pole.  Done.