A diode is a one way check valve basically. it will let current pass one way but not the other.
Remove it first (typically just unscrews, may require narrow wrench and turning from the solenoid top). Determine the solenoid action (for example, when turning the key to on, does the solenoid have continuous power? Does the solenoid pin/plunger move up or down with power?). Permanently set the solenoid to allow fuel to flow, this can sometimes be done by cutting the pin/plunger part off, or pulling it out, there is a spring that may also need to be removed. Put the solenoid back in and make sure all seals are OK or add new ones. Note after bypassing a fuel solenoid, if you do not intent to replace it soon, you should install a fuel shut off valve when can be purchased from auto parts stores or big box hardware stores for 5-10 dollars. To prevent backfire, you would need to switch off the fuel and wait for the engine to stall which can take up to a few minutes. Turning the engine off with the key will still work, however you will not be protected from backfiring which can damage the engine. Turning the engine off by pulling the throttle back all the way will also not help.
It sounds like the solenoid is working but the starter is not. Check the wires on the starter. Possibly the starter has gone bad.
its beside the shifter under the console. if your car is stuck in park, take off the console, and pull the shift solenoid out or engage it and then zip tie it to a bracket that doesn't move. and it will work from now on.
Overdrive might not work on a 1992 Dakota because there is a problem with the transmission. The shift solenoid or a belt is not functioning properly inside the transmission.
Check all fuses to include those in engine bay, then all connections of battery cables - not just the ones at the battery posts. Start using a little logic and find out what's wrong before replacing more parts. Power directly to the low side of the solenoid should force the starter. If that works but the starter doesn't work with the keyswitch, it might just be the neutral lockout.