Help...I'm trying to wire a GM CS130 alternator into my stock 1971 FJ40. I bought the plug that goes to the alt. and wired it according to a wiring diagram I saw online. It doesn't charge. Autobone checked out the alt. and said it was good. Any ideas?

Shawn
'71 FJ40

P.S. Bring on the newbie insults. I've been lurking for a while, but finally had a problem so bad I had to register and post.

I know it would have been said soon enough, so I might as well do it....

www.ih8mud.com

Check your wiring with the write ups on that site. That's how I did mine, and that is where everyone is referred to when they ask this question. Good luck-

Right, I may be a newbie but I'm not that dumb. If I recall correctly, there are two links on there for the GMFJ40 alt. One is how to install the alt but not how to wire it, and the other is for the old style GM alternator. I need to know how to wire up the CS130 alternator, which is the newer GM alternator. Thanks. Please keep the help coming.

Heres the sh*t for a link! www.alternatorparts.com

I am wiring one in my FJ40 right now and the CS130 is DIFFERENT than any other early GM alt. The +(batt)goes to the battery. Use 4 GA wire, as these beasts can put out 100+ amps. There is a plug with four wires, starting with the big wire(it has the larger of the four pins) they are:

S-connect this right to the "+" on the Alt. with a ring terminal
F-Not needed
L-Connect to 12V source with a 3-4Watt bulb in the circuit(see web page on CS130 repair)
P-Not used

The 3-4watt bulb will be the charge waring light in the truck now. DO NOT USE THE AMP GAUGE!!!! USE the 4 gauge wire and run it straight to the battery from the battery terminal on the alt.

Hope that helps...

Oh, one more thing: some regulators have an "I" in the place of the "L", so check the black plastic on the alternator where the plug plugs into. there will be small letters and the "I" version uses slightly different wiring....

When you've got it set guys, post a reply here and I'll add the information to ih8mud.com!!

Do I have to use the bulb? Can I just put a resistor (value?) or something in there?

Thanks a lot for the help. I'll try this out tonight and hopefully it will work.

Originally posted by Jones'n
Do I have to use the bulb? Can I just put a resistor (value?) or something in there?

Thanks a lot for the help. I'll try this out tonight and hopefully it will work.

This came up on the General board a few months ago. the consensus is that you need some resistance, but most people like to use a bulb as it also indicates when it is working.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=24251&highlight=CS130

I'll agree with Pin Head. You can use a resistor(check the website for actual values)

Check page 6 of this writeup:
http://www.alternatorparts.com/cs130_sbpage1.htm

What the bulb does is act as resistance for the cirucuit to drop the voltage down. When the alternator is not functioning properly, ie high or low voltage, or not charging the light will light. It is now your charging monitor, since you should not be subjecting the AMP gauge to that much max load(100+ amps) since yours is likely only scaled to +/- 30.

What I would recommend doing is tapping off the IGN hot to the coil(black and yellow) and running this to the alternator, with a stop at the dash for the light previously. There should be a IGN hot that runs to the voltage regulator, so find this with a voltmeter and use this as the switch 12V. run it through the dash to the light and back to the "L" terminal of the alt. Disconnect the white/blue wire for the alt(the +batt one) and tape it off. Run the 4 ga wire to the battery.

This thread is just in time for me. I am installing a 350 engine with a new 180amp alternator (ebay) into my 75 fj55. Mike Robison has a great write up on installing GM alternators into LC electrical system on I8mud. With this high amp alternator, I will use a 4 gauge wire to the battery and eliminating the LC external voltage regulator. This alternator has the bat hookup and two other wires. I will have sufficent power now to run all my lights and a converter and anything else I want.

The whole reason this all came about is because I'm installing a Centech wiring harness that's set up for a GM alternator. I just decided it was the perfect time to switch to a higher amp more readily available alternator. I just happened to grab the CS130 from the junkyard before I knew anything about them. I would switch to a different one, but I already butchered my alternator mount to get this to fit, so I would like to get it working. I'll try the suggestions tonight and hopefully it'll work.

These alternators also have a habit of not charging when the battery is low. So charge the battery before you test this out, becasue a dead battery will prevent them from charging...

I tried wiring this up last night, and when I turn the key the light doesn't come on. When I jump the plug straight to ground, the light comes on, but when I plug the connection into the alternator the light will not come on. Does this mean that for some reason the alternator is not grounded properly? If so, how do I ground the alternator? Thanks for the help.

It might depend on what regulator the alternator has. The "L" style should light when this is done when the ign is on but engine not running. The alternator should ground through the bolts and bracket. Just to test that out, ground the wire to the body of the alt and check the light. Should come on then. Make sure the large wire (S) goes to the battery wire terminal. the L terminal should be the third pin, counting from the end with the large end. My light did not come on when I had the + terminal on the alt off the battery connector. This may all be different with the "I" style regulators, so check.

-Brett

Thanks for the help. I finally got a chance to mess with this this weekend. I have the "L" style regulator. I have switched 12v from the fuse block to one of the little dash lights to the "L" pin. The "S" pin jumps to the big "+" lug, which is wired to the + batt terminal. The light never comes on. My battery voltage reads 12.4 when off, and 14.7 with the engine running, so it looks like the alt is working. Should I worry about the light or should I just run it and call it good? The light does come on if I just bypass the alternator and go straight to ground with it, so I know the light is good. Thanks.