How to Check an Automotive Points Condenser

An automotive condenser is actually a capacitor that was used in early distributors with points. The condenser is typically mounted in the distributor next to the points. The condenser’s objective is to absorb the current feedback to the points as the coil’s primary is collapsed. This phenomenon is caused by secondary crossover and, small as it may be, is strong enough current to cause damage to the points surface by allowing them to arc when they are opened. The condenser absorbs this current, thereby curtailing the damage to the points.

Things You'll Need

  • Flat-head screwdriver
  • Phillips screwdriver
  • Volt/Ohmmeter
  • Needle-nose pliers
  • Make sure the ignition is off. Remove the distributor cap, using a flat-head screwdriver. Remove the rotor, using a Phillips screwdriver, if it cannot be pulled off by hand. Remove the condenser connector on the points, using needle nose pliers. Isolate the connector so it does not touch metal.

  • Switch the voltmeter to the Ohms scale. Place the Ohmmeter red probe on the wire connector to the condenser and the black probe on the condenser body. The display must jump to 0 resistance initially and begin to climb rapidly to infinity as the Ohmmeter charges the condenser.

  • Switch the probes around with the red probe on the condenser body and the black probe on the wire connector. The Ohmmeter should continue to rise as the condenser is charged by the Ohmmeter.

  • Consider the readings obtained when testing the condenser. If the resistance held steady without rising steadily or showed no resistance to ground and remained so, the condenser is bad. If the tests were as described, the condenser is good.

  • Remove the Phillips screw in the base of the condenser and lift it off. Install a new condenser and tighten the screw. Install the condenser wire connector to the points in series with the ground wire to the distributor. Install the rotor and distributor cap.