How do you determine whether the alternator in a 2004 Chevy Tahoe Z71 is 105 amp or 145 amp?

There's no easy way to visually determine the amperage of a 2004 Chevy Tahoe Z71 alternator without removing it and checking the label or part number. The alternator itself usually doesn't have a clearly visible "105A" or "145A" marking.

Here's how to figure it out:

1. Check the alternator's part number: The most reliable method. Once the alternator is removed (or if you can see a clear part number without removal), look up the part number online using a parts website like AutoZone, Advance Auto Parts, Napa Auto Parts, or a GM parts website. The description for that part number will specify the amperage.

2. Check your Tahoe's build sheet or owner's manual (less reliable): Your owner's manual *might* list alternator specifications, but this is not guaranteed. A build sheet (if you can find it) might provide more detailed information.

3. Look at the alternator's physical size (least reliable): Larger alternators generally have higher amperage, but this isn't definitive. Different manufacturers use different designs, so size is not a reliable indicator.

4. Check wiring: The gauge of the wiring leading to and from the alternator might give a clue, but this is highly unreliable and not recommended as a primary method. Heavier gauge wire usually indicates a higher amperage alternator, but there's no guarantee.

In summary, the most accurate method is to locate the alternator's part number and look it up using online parts resources. This will remove any guesswork.