Here a tutorial on how to install the headphone jack cable: iPod Classic Headphone Jack & Hold Switch Replacement
Here a link to the part: iPod Classic (Thin) Headphone Jack & Hold Switch
iFixit will ship to Mexico with the following cravat: international shipments may be subject to import taxes and/or customs fees. These fees are the sole responsibility of the recipient. If a shipment is refused and returned, you will be responsible for any import taxes and/or return shipping costs incurred by iFixit.
Includes headphone jack & hold switch — 2 available at 14.95 each.