Ringing is common. That is a "switch-mode" power supply regulator similar to those used in vcrs. Chrysler had very little computer trouble in the early '90s. What have you checked so far? Do you have spark? Do you hear the fuel pump hum for one second when you turn on the ignition switch? Have you checked the Engine Computer for diagnostic fault codes? Is the Check Engine light staying on?
You can back-probe the connector pins for the Engine Computer and compare the voltages to what you'd expect from the service manual listings, but that is going to waste a lot of time and not be very informative because every circuit or system uses only a few wires. What you're wanting to do is a very common method of troubleshooting tvs and vcrs, but with their integrated circuits a problem on one pin can affect so many things it's hard to narrow down without testing everything.
In your case the best place to start is with the symptoms. If you do not have spark, measure the voltage on the dark green / orange wire to the ignition coil or coil pack, any injector, or either small wire on the back of the alternator. You should find full battery voltage for one second after the ignition switch is turned to "run". What is important is that voltage must come back during engine cranking.
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Saturday, June 11th, 2011 AT 3:28 AM