How To Test The Starter Motor (1991-1995 3.9L Dodge Dakota)

TEST 6: Making Sure The Starter Motor Relay Is Getting An Activation Signal

If you've reached this point, you have confirmed that:

• Your Dodge Dakota's starter motor cranks the engine only when the starter motor relay is bypassed (TEST 1).
• The starter DOES NOT crank the engine when the starter motor relay is in its place in the Power Distribution Center.

If the above two test results apply to your particular situation then there's a good chance that the starter motor relay is not getting an activation signal (of 12 Volts) from the ignition switch.

This activation signal is fed to the starter motor relay by the female terminal labeled with the letter A in the illustration above.

In this test section, we're gonna' make sure this activation signal is present when you turn the key to crank and start the engine.

These are the test steps:

1. 1

   Remove the starter motor relay from Power Distribution Center.

2. 2

   Connect the red multimeter test lead to the female terminal labeled with the letter A in the illustration above.
   
   NOTE: Gently probe the female terminal in the relay socket with your multimeter test lead to avoid damaging it.

3. 3

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

4. 4

   Depress the clutch pedal till it bottoms out (standard transmission equipped Dodge Dakota only).
   
   This test will not function without depressing the clutch pedal (standard transmission only).

5. 5

   Have your helper turn the key to crank the engine.
   
   NOTE: The engine is not gonna' start but to check for the relay's activation signal you need to have your helper turn the key to start the engine.

6. 6

   Your multimeter should read 10 to 12 Volts DC.

Let's examine your test results:

CASE 1: 10 to 12 Volts are present when the key is turned to start the engine. This is the correct test result and it lets you know that your Dodge Dakota's starter motor relay is getting an activation signal from the ignition switch.

The next step is to check that the park/neutral safety switch is providing Ground for the starter motor relay. For this test go to: TEST 7: Testing The Park/Neutral Safety Switch Signal.

CASE 2: 10 to 12 Volts ARE NOT present when the key is turned to start the engine. Without a Start Signal the starter motor relay will not activate the starter motor.

AUTOMATIC TRANSMISSION: The most likely cause of this missing starter motor relay activation signal is a bad ignition switch. Your next step is to test the ignition switch.

STANDARD TRANSMISSION: The most likely cause of this missing starter motor relay activation signal is a bad ignition switch or a bad clutch switch. Your next step is to test the ignition switch and the clutch switch.

TEST 7: Testing The Park/Neutral Safety Switch Signal

So far you have confirmed that:

• Your Dodge Dakota's starter motor cranks the engine only when the starter motor relay is bypassed (TEST 1).
• The starter DOES NOT crank the engine when the starter motor relay is in its place on Power Distribution Center.
• The starter motor relay is getting an activation signal from the ignition switch (TEST 6).

In this test section, we're gonna' make sure that the relay's activation signal has a good path to Ground.

The terminal that supplies this path to Ground is the female terminal labeled with the letter C (see the illustration above).

If your 1991-1995 3.9L V6 Dodge Dakota has an automatic transmission, the neutral safety switch provides this path to Ground.

If your 1994-1995 3.9L V6 Dodge Dakota has a standard transmission, Ground will be present at all times (the clutch safety switch is not part of this circuit).

NOTE: If your 3.9L Dodge Dakota is equipped with an automatic transmission, the transmission must be in Park or Neutral for this test to work.

These are the test steps:

1. 1

   Disconnect the starter motor relay from its connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Probe the female terminal labeled with the letter C with the black multimeter test lead.

4. 4

   Connect the red multimeter test lead to the battery positive (+) terminal.

5. 5

   The multimeter should read 10 to 12 Volts DC with the automatic transmission in Park.
   
   If your Dodge Dakota has a standard transmission, Ground should be present at all times.

Let's examine your test results:

CASE 1: Your multimeter registered 10 to 12 Volts. This is the correct test result and it confirms that the starter motor relay's activation signal has a good path to Ground.

If your 3.9L V6 Dodge Dakota has an automatic transmission, you can conclude that the park/neutral safety switch is OK.

You can conclude that the starter motor relay is bad and needs to be replaced only if you have:

• Confirmed that the starter motor cranks the engine only when the starter motor relay is bypassed (TEST 1).
• Confirmed that the starter motor DOES NOT crank the engine when the starter motor relay is in its place on Power Distribution Center.
• Confirmed that the starter motor relay is getting an activation signal from the ignition switch (TEST 6).
• Confirmed that female terminal C has Ground present.

CASE 2: Your multimeter DID NOT register 10 to 12 Volts. This test result lets you know that the starter motor relay's activation signal does not have a good path to Ground.

Without this path to Ground, the starter motor relay will not activate the starter motor.

On the automatic transmission equipped 3.9L Dodge Dakota, this test result usually tells you that the park/neutral safety switch is bad.

On the standard transmission equipped 3.9L Dodge Dakota, this test result lets you know that the Ground wire that connects to female terminal C has an open-circuit problem between the Power Distribution Center and where it connects to Ground on the engine or chassis.

Bypassing The Starter Motor Relay Is Not A Repair Solution

If bypassing the starter motor relay got your 3.9L V6 Dodge Dakota (equipped with an automatic transmission) to finally crank and start, don't be tempted to consider this the repair solution for your 3.9L V6 Dodge Dakota.

Bypassing the starter motor relay is only a test procedure and not a repair. Why? Because bypassing the starter motor relay eliminates a very important safety precaution built into the starter motor system circuit.

To be a bit more specific: It eliminates the neutral/safety switch from the system. This means that the engine can start in any gear! By any gear I mean that it can start in Drive or Reverse.

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