alternator wires

[kawman10]

So my battery wasn't holding charge, so I took my alternator to get tested at the local advance auto parts. So they put it on and without them turning the equipment on, it was reading that it was charging. So they told me to replace it, which i bought a new one. My question to you guys is, i have a brown and a red wire going into the alternator. if you looking at the alternator from the front of the truck which side do the wires go into it? also my old one was never grounded, do I need to ground the alternator?

thanks all

[mnunn454]

In layman's terms, the heavy red wire connects to the alternator's output. It's probably a AWG 10 diameter if memory serves. It gets bolted to the big (#12-32?) single pole threaded terminal sticking out of the alternator.

Little brown wire (about a #18 or 20 AWG) goes to the plug in terminal and excites the alternator's field so the alternator will know how much amperage to produce.

No, the alternator doesn't need grounding. It already is by virtue of the engine brackets its bolted to.

There's also some decent threads with pictures on this if you'll use the "search this forum" button.