The fuel system's operation depends on:
* The ignition system: The engine control module (ECM) controls fuel delivery based on various sensors. Turning the key to "off" breaks the circuit, ultimately halting fuel flow.
* Inertia switch (crash sensor): This safety device shuts off fuel in a collision. Its location varies by model and may be under the dash or in the engine compartment.
* Fuel pump relay (possibly): Some models might have a dedicated relay for the fuel pump. This relay's failure would prevent fuel delivery, effectively acting as a fuel shut-off. This isn't a *fuel shut-off* relay, but rather a component relay critical to the fuel pump's function.
* ECM (Engine Control Module): This is the brain of the operation; it controls fuel delivery based on many inputs and is the ultimate controller. A fault here could also prevent fuel flow.
To find potential trouble areas:
1. Consult your owner's manual: This is the best starting point for relay locations specific to your *exact* 1989 Dodge model (e.g., Caravan, Ram 50, Dakota, etc.). The manual might list relay locations and their functions.
2. Check the Power Distribution Center (PDC): This is usually a large fuse and relay box, often located under the hood or in the dash. Look for relays labeled "fuel pump" or related terminology.
3. Under-dash fuse box: Also check for any relays in your under-dash fuse box.
4. Online forums: Search Dodge forums specifically for your model year and model; someone might have already dealt with a similar issue and documented relay locations.
Important Note: Working on a fuel system involves potential fire hazards. If you're not comfortable with automotive electrical work, take your vehicle to a qualified mechanic. Incorrectly diagnosing and fixing fuel system issues can be dangerous.
