To be certain, you should:
* Consult your vehicle's repair manual: This is the most reliable source for the precise location.
* Search online for images: Search for "2002 Dodge Ram diesel TCM location" on image search engines like Google Images. This will show you pictures of the TCM's location on similar vehicles.
Be aware that accessing the TCM may require removing some components for better visibility. Always disconnect the battery's negative terminal before working near electrical components.