I have a 99 Silverado that came with a 105 amp alterntor. I stopped at the junkyard and picked up a 145 amp for $75. It still has the connector from the truck it came off of, but the little plug has 3 wires coming out, versus my stock 1.

Is this a problem, and how do I fix it?

 

I'm not sure you'll be able to use that one. Try just hooking up the L terminal wire (that should be the one your stock 99 uses), but I think that style alternator needs the F terminal energized as well to make the alt "turn on".

I think that's right anyway, I did a bunch of research on these awhile back. IIRC you can use an older 2-wire alt on a newer truck but you have to turn off the alternator codes cause your battery light will be on, but I don't think you can use a newer alt on an older truck.

 

I'm going to hook it up, just to see what it will do. I have hptuners, so I can disable codes if need be - I just want to know if it will charge.

 

just put your single wire in the same spot on the plug as the old one
it should work

 

It worked fine. I did have to get a longer belt. Driving to the parts store with no power steering sucked.

What do those other two wires on the newer trucks do?

EDIT: Kingpimp is my older brother.

 

Pretty sure that the other wires are for the PCM...it has some sort of alternator duty cycle. When I swapped in my 02 PCM, I also had to run a from the PCM to the alternator to turn of a blinking battery light...as well as swap in a newer alternator (hence the 145 amp alt I currently have ) There used to be a thread by creederado that detailed his 05 efan swap, 145 amp alt, etc. The thread has part numbers and all. I linked to it in one of the stickies in the General section I believe....

 

The 05+ have two wires. I found this out last night when an 06 alternator arrived on my door only to end up back in the box on my shelf. My 04 has 3 wires. Wish I had known before lol.

I think were both out of luck as far as getting these alts to work.

-Lurius

 

Dude, it works fine. I did swap my 99 pcm for an 02, though. So far it was bolt-on and just get a longer belt. I am seeing less draw when my subs hits while the e-fans, lights, and heater are on.

Try swapping it in, it took me maybe 15 minutes. Maybe you can just swap it in and see if it chrages.

 

buy it on ebay?

 

I got mine from an ebay auction by G&R Auto Parts...

p.s.; I now have 2 wires and originally had one.