How To Test The Ignition System (1993-1995 2.5L Caravan And Voyager)

TEST 4: Making Sure The Ignition Coil Is Getting 12 Volts

As you're already aware, the ignition coil's electrical connector has two wires.

The wire that feeds the ignition coil with 12 Volts is the dark green with orange stripe (DK GRN/ORG) wire.

The DK GRN/ORG wire connects to the female terminal labeled with the number 2 in the photo above.

We'll do a simple multimeter voltage test to verify the presence of these 12 Volts in the DK GRN/ORG wire.

CAUTION: To check for the presence of 12 Volts you must crank the engine. Be careful and take all necessary safety precautions!

These are the test steps:

1. 1

   Select Volts DC mode on your multimeter.

2. 2

   Disconnect the ignition coil from its electrical connector.

3. 3

   Connect the red multimeter test lead to the DK GRN/ORG wire.

4. 4

   Connect the black lead of the multimeter to the battery (-) negative terminal.

5. 5

   Have your helper crank the engine while you observe the multimeter.

6. 6

   You should see 10 to 12 Volts on the multimeter.

Let's analyze your test result:

CASE 1: DK GRN/ORG wire is supplying the ignition coil with 10 to 12 Volts DC. This is the correct test result and it tells you that the ignition coil is getting power.

Since the ignition coil does not fire spark, the next step is to check that the ignition coil is receiving an activation signal. Go to: TEST 5: Testing The Ignition Coil's Activation Signal.

CASE 2: DK GRN/ORG wire IS NOT supplying the ignition coil with 10 to 12 Volts DC. Without power the ignition coil will not fire spark.

This lack of spark will be caused by one of the following:

• An open-circuit problem in the DK GRN/ORG wire between the ignition coil's connector and the ASD relay.

TEST 5: Testing The Ignition Coil's Activation Signal

Up to this point, your tests have confirmed that:

• All four spark plug wires are not sparking (TEST 1).
• The ignition coil's high tension wire is not sparking (TEST 2).
• The ignition coil's tower is not sparking (TEST 3).
• The ignition coil is getting 10 to 12 Volts (TEST 4).

For our last test, and the test that will let us know if the ignition coil is bad, we're gonna test for the presence of the ignition coil's activation signal.

We'll use an LED light to check for the presence of this activation signal. You can see an example of this tool and where to buy it here: The LED Light Test Tool And How To Make One (at: easyautodiagnostics.com).

NOTE: LEDs are polarity specific and so their wires will be black and red. This also means that the red and black leads must be connected in a very specific way to get a correct test result.

Let's get started:

1. 1

   Disconnect the ignition coil from its electrical connector.

2. 2

   Connect red LED wire to the dark green with orange stripe (DK GRN/ORG) wire of the ignition coil's 2-wire connector.
   
   This is the wire that feeds 12 Volts to the ignition coil and it's labeled with the number 2 in the photo above.

3. 3

   Connect black LED wire to the GRY (or BLK/GRY) wire of the ignition coil's 2-wire connector.
   
   This is the wire that feeds the activation signal to the ignition coil and it's labeled with the number 1 in the photo above.

4. 4

   Have an assistant crank the engine.

5. 5

   The LED light should blink on and off the whole time the engine is being cranked.
   
   NOTE: Don't worry about what the LED light does before or after your helper starts cranking the engine. The only results you're interested in interpreting are the results obtained with the engine cranking.

Let's find out what your test result means:

CASE 1: The LED flashed ON and OFF. This is the correct test result and confirms that the ignition coil is receiving an activation signal.

You can conclude that the ignition coil, on your 2.5L Dodge Caravan (Plymouth Voyager), is bad only if you have:

• Confirmed that all four spark plug wires are not sparking (TEST 1).
• Confirmed that ignition coil's high tension wire is not sparking (TEST 2).
• Confirmed that the ignition coil's tower does not spark (TEST 3).
• Confirmed that the ignition coil is getting 10 to 12 Volts (TEST 4).
• Confirmed that the ignition coil is getting an activation signal (this test section).

Here's why: If the ignition coil is getting 10 to 12 Volts (TEST 4) and it's getting an activation signal (TEST 5), then it has to spark. Since your test result confirms that it does not spark, you can conclude that the ignition coil is defective.

Replace the ignition coil to solve the no-start problem on your 2.5L Dodge Caravan (Plymouth Voyager).

CASE 2: The LED DID NOT flash ON and OFF. Without the activation signal the ignition coil will not spark.

Re-check all of your connections and repeat the test. If the LED light does not flash on and off then the most likely cause of this missing signal is a bad distributor pickup coil.

Testing the distributor pickup coil can easily be done with a multimeter. The following tutorial will help you test the distributor pickup coil:

• How To Test The Distributor Pickup Coil (1991-1995 2.5L Caravan And Voyager).