How To Test The Ford Ignition Control Module (Distributor Mounted)

TEST INFO: Circuit Descriptions

Here are brief descriptions of the circuits that we'll be testing. You'll notice that there are no wire color descriptions. This is intentional. The color of the wires in the illustration will not match the ones on your vehicle.

The good news is that no matter what color the wires are (on the vehicle), the circuit descriptions DO NOT CHANGE. You will be able to successfully diagnose this no-start condition with this information.

IMPORTANT: It will be necessary to test some of these circuits while the engine is being cranked. Be careful, use common sense and take all necessary safety precautions.

Ignition Control Module Connector

1. 1- Profile Ignition Pickup (PIP) Signal.
2. 2- Spout.
3. 3- 12 V at START.
4. 4- 12 Volts (gray module) or IDM circuit (black module).
5. 5- Ignition Coil Control Signal.
6. 6- Ground.

TEST 1: Checking For Power (12 V)

We'll begin by checking that the ignition control module is receiving 12 Volts.

I recommend using a wire-piercing probe to accomplish all of the tests in this article. (Wire Piercing Probe). Whatever method you use, the key here is to be careful. Remember to use common sense and take all safety precautions.

IMPORTANT: The ignition coil, ignition control module and the PIP sensor receive 12 Volts from the same circuit. So if you test one, you're also testing the others for voltage.

Here are the test steps:

1. 1

   Disconnect the ICM from its electrical connector.

2. 2

   Put the multimeter in Volts DC mode.

3. 3

   With the red multimeter test lead and a suitable tool, probe the number 4 circuit wire of the connector.
   
   NOTE: Don't probe the front of the connector or you'll damage the female terminal (inside the connector).

4. 4

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

5. 5

   Turn key on but don't crank or start the engine.

6. 6

   Your multimeter should register 10 to 12 Volts DC.

Let's take a look at what your test results mean:

CASE 1: The multimeter registered 10 to 12 Volts DC. All is good in the neighborhood, since this multimeter test result lets you know that the ignition control module and ignition coil are getting power.

The next test is to check that the ignition control module is getting Ground. For this test go to: TEST 2: Testing The Ground Circuit.

CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Double-check that you're testing the correct wire on the ignition control module (ICM).

If your multimeter still does not register 10 to 12 Volts DC, then you must find out why you're missing this voltage.

Without this voltage the ignition control module, ignition coil, and the PIP sensor will not work.

Restoring power to this circuit should get your vehicle's engine to start.

TEST 2: Testing The Ground Circuit

Now that you've confirmed that the ignition control module (ICM) is getting power (10 to 12 Volts DC) in TEST 1, we'll check that the ignition control module (ICM) is receiving Ground.

The wire that feeds the ICM Ground is the number 6 circuit of the ignition module connector.

Alright, this is what you'll need to do:

1. 1

   Put the multimeter in Volts DC mode.

2. 2

   Connect the black multimeter test lead to the ignition module connector's number 6 circuit wire (with the appropriate probe).

3. 3

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

4. 4

   Your multimeter should register 12 Volts DC.

Let's examine your test result:

CASE 1: The multimeter registered 12 Volts DC. All is good in the neighborhood, since this test result confirms that your Ford's ignition control module is getting Ground.

The next test is to check that the ignition control module (ICM) is activating the ignition coil to fire spark, for this test go to: TEST 3: Ignition Coil Switching Signal.

CASE 2: The multimeter DID NOT register 12 Volts DC. Re-check your multimeter connections and make sure you're testing the correct wire.

If your multimeter still doesn't indicate a voltage between 10 to 12 Volts DC; then this means there is an open in this wire. Without this Ground the ignition module will not function. Repairing the circuit (or adding Ground) should get your engine to start.