* Ignition Control Module (ICM): This is a common failure point in many vehicles, including older Dodge Caravans. The ICM receives signals from the CKP and CMP and controls the firing of the coil pack. A faulty ICM will prevent spark entirely. This is high on the suspect list given you've already replaced other components.
* Power to the Ignition System: Check the fuses and relays associated with the ignition system. A blown fuse or bad relay will cut power to essential components. The wiring itself could also be damaged or corroded, preventing power from reaching the components. Inspect wiring harnesses carefully, especially near connectors.
* Ignition Switch: A malfunctioning ignition switch might not be sending the correct signal to power the ignition system, preventing the ICM from operating correctly.
* PCM (Powertrain Control Module): Though less likely after replacing the sensors, the PCM is the "brain" of the engine's electronics. If it's faulty, it may not be sending the correct signals to the ICM, even if all sensors are working. Diagnosing a PCM issue usually requires specialized tools.
* Wiring Harness Issues: A break or short in the wiring harness between any of the components (PCM, ICM, coil, sensors) could interrupt the signal flow. Inspect carefully for any damage.
* Distributor (If Equipped): While many 1996 Grand Caravans used a DIS (Distributorless Ignition System), some might have a distributor. If yours does, check the rotor, cap, and internal components for wear or damage. (If it's DIS, you can disregard this point.)
Troubleshooting Steps:
1. Visual Inspection: Carefully examine all wiring, connectors, and components for any obvious damage, corrosion, or loose connections. Pay close attention to the ICM and its wiring.
2. Check for Power and Ground: Use a multimeter to check for power and ground at the ICM and coil pack connectors. You'll need a wiring diagram to identify the correct wires.
3. Test the ICM: This often requires a multimeter and specialized knowledge or access to a diagnostic scanner. There are online tutorials that show you how to test the ICM, but be cautious working with automotive electronics.
4. Test the Ignition Switch: This requires some electrical knowledge and testing with a multimeter to ensure it's sending the appropriate signals.
5. Professional Diagnosis: If you're not comfortable with automotive electrical troubleshooting, it's best to take the vehicle to a qualified mechanic. They have the tools and experience to diagnose the problem accurately and efficiently. A scan tool can read codes from the PCM that may indicate the problem.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components. Working on a vehicle's electrical system can be dangerous if you're not experienced.
