To find it, you'll need to:
1. Consult your owner's manual: This is the best resource. The manual should have a diagram showing the location of all important connectors, including the diagnostic port.
2. Look under the dash: It's most commonly found somewhere under the dashboard, often near the steering column or on the center console. It might be tucked away and hard to see.
3. Check online forums and resources: Search online forums specific to your 1988 Jeep model (e.g., "1988 Jeep Cherokee diagnostic port location"). Other owners may have posted pictures or descriptions of its location.
4. Look in the engine compartment (less likely): While less common for the main diagnostic port in that year, some rudimentary diagnostic connectors might be found under the hood.
Important Note: 1988 Jeeps use OBD-I, which is a very basic diagnostic system compared to later OBD-II systems. The information you can get from it will be limited. You might need a specific OBD-I scan tool for your Jeep's year and model to interpret the codes.