Because its exact location can vary slightly depending on specific options and modifications the truck may have had over the years, the best approach is to:
1. Consult your owner's manual: If you have it, this is the most reliable source. The manual should have a diagram showing the fuel filter's location.
2. Use a repair manual: A Haynes or Chilton repair manual for your specific year and model will have detailed diagrams and instructions.
3. Search online: Use a search engine like Google, Bing or DuckDuckGo and search for "1990 Dodge Ram 2500 360 fuel filter location". You might find images or forum posts from other owners who have worked on similar trucks.
Remember to be cautious when working with fuel lines and the fuel filter. Fuel is flammable, so take appropriate safety precautions. If you're not comfortable working on this yourself, it's best to take your truck to a qualified mechanic.