* Faulty ignition switch wiring: Even though you replaced the switch, the wiring harness connecting to it might be damaged or corroded. Check the wires for breaks, chafing, or corrosion, particularly at the connection points. Pay close attention to the wire responsible for sending power to the solenoid when the key is in the "start" position.
* Faulty Neutral Safety Switch (NSS): This switch prevents the car from starting unless the transmission is in park or neutral. A faulty NSS will prevent power from reaching the starter, even with a good ignition switch. Locate this switch (usually on the transmission) and test its continuity with a multimeter. It should show continuity only when the gear selector is in park or neutral.
* Faulty Starter Relay (or similar component): Some vehicles use a relay to control the high current flow to the starter. If this relay is faulty, it won't allow the current to pass, even though the ignition switch is sending the signal. This is less likely given your ability to jump the solenoid, but it's worth investigating if you're familiar with electrical systems. This relay might be integrated into a bigger module such as a Power Distribution Module (PDM).
* Bad ground connection: A poor ground connection between the engine or chassis and the battery can also prevent the starter from receiving sufficient current. Clean all ground connections, especially those near the engine and battery.
Troubleshooting Steps:
1. Visual Inspection: Carefully examine all wiring related to the ignition system, focusing on the area around the ignition switch and the starter solenoid. Look for broken, frayed, or corroded wires.
2. Continuity Test: Use a multimeter to test the continuity of the wires between the ignition switch and the starter solenoid in the "start" position. You'll need a wiring diagram for your specific Beretta model to identify the correct wires.
3. Neutral Safety Switch Test: Test the NSS as described above.
4. Ground Connection Inspection: Thoroughly clean all ground connections.
5. Relay/PDM Test (if applicable): If you suspect a relay problem, find its location and test it or have it tested.
Important Note: Working with car wiring requires caution. Disconnect the negative battery terminal before working on any electrical components. If you are not comfortable working with car electrical systems, it's best to take your car to a qualified mechanic. A wiring diagram specific to your 1994 Beretta will be very helpful in diagnosing this issue. You can often find these online through auto repair websites or forums.
