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How to Troubleshoot the Ignition System in a Mercury Villager

by ContributorUpdated November 07, 2017

Items you will need

  • Ohmmeter

  • Spark tester

How to Troubleshoot the Ignition System in a Mercury Villager. The discontinued Mercury Villager never had a distributorless ignition system, so you are more free to test more components if an ignition problem arises. There can be different ways to do it, however, depending on the engine size. Verify all the vacuum lines and spark plug wires are properly routed and securely connected, the battery is fully charged and all accessories are turned off before troubleshooting the ignition system.

Spark and Coil Testing

Measure the Villager's spark plug wire resistance. Remove the wire from the distributor cap and spark plug and connect an ohmmeter to each end of the wire. The resistance should be 4,150 to 5,610 ohms per foot. Reconnect the wire afterward.

Connect a spark tester to a spark plug wire disconnected from the plug. Ground the tester to an appropriate location on the engine. Crank the engine and look for a blue spark on the tester.

Attach a 12-volt test light to the battery's positive terminal. Disconnect the ignition coil harness connector with the ignition off and probe the connector's green wire (pin 2) terminal. The light should flash rapidly when you crank the engine.

Test the ignition coil's primary resistance. Disconnect the negative battery cable, leave the harness connector off and connect the ohmmeter to coil pins 1 and 2. The resistance should be about 1 ohm.

Check the secondary resistance. Connect the ohmmeter to coil pin 1 and the coil wire tower tip on the distributor. The resistance should be around 10,000 ohms on a 3.0L engine or 12,000 for a 3.3L engine.

Use the ohmmeter to test the power transistors. This procedure varies depending on whether your car has a 3.0L or 3.3L engine.

Power Transistor Testing a 3.0L Engine

Disconnect the Villager's negative battery cable.

Remove the power transistor harness connector.

Connect the ohmmeter's positive lead to transistor terminal A and the negative lead to terminal B. The resistance should be at least 10,000 ohms.

Power Transistor Testing a 3.3L Engine

Disconnect the negative battery cable.

Remove the coil harness and distributor harness connectors from the distributor.

Connect the ohmmeter to pin 2 of the distributor terminal and the pin 2 terminal of the electrical connector. The resistance should be greater than 0 ohms.


Don't let the test light contact any metal parts of the car while it's connected to the positive battery terminal.

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