Volkswagen Golf/Jetta/Cabriole 1990-1999

Ignition Control Unit

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Testing




WARNING
Testing the ignition control unit requires the use of a high impedance digital volt/ohm meter (DVOM) or LED test light. A standard analog voltmeter or incandescent light may cause damage to the unit.

CIS and CIS-E, FOX
voltage supply check
  1. Unplug the harness connector from the ignition control unit.
  2.  
  3. Using a digital voltmeter, connect the meter positive lead to terminal 4 and the negative lead to terminal 2 of the harness connector.
  4.  
  5. With the leads connected, turn the ignition switch ON and check for battery (12 volts) voltage.
  6.  
  7. If voltage does not exist, inspect the integrity of the wiring, and/or refer to the wiring diagrams in .
  8.  
  9. If 12 volts exists at the harness connector, proceed with the Component Check procedure.
  10.  

Component check
  1. Unplug the harness connector from the Hall sender at the distributor.
  2.  
  3. Using a digital multimeter switched to the 20V range, connect the meter positive lead to terminal 15 and the negative lead to terminal 1 of the ignition coil.
  4.  
  5. Turn the ignition switch to the ON position. The meter must read a 2 volt minimum, then drop to 0 volts after 1-2 seconds.
  6.  
  7. If not, replace the Hall control unit and the ignition coil.
  8.  
  9. Using a jumper wire, briefly touch the center wire of the distributor harness connector to ground. Displayed voltage must rise briefly to at least 2 volts.
  10.  
  11. If not, replace the Hall control unit and the ignition coil.
  12.  

Digifant II Systems Only
voltage supply check


Click image to see an enlarged view

Fig. Checking for ignition control unit voltage at the harness connector

  1. Unplug the harness connector from the ignition control unit.
  2.  
  3. Using a digital voltmeter, connect the meter positive lead to terminal 4 and the negative lead to terminal 2 of the harness connector.
  4.  
  5. With the leads connected, turn the ignition switch ON and check for battery (12 volts) voltage.
  6.  
  7. If voltage does not exist, inspect the integrity of the wiring, and/or refer to the wiring diagrams in .
  8.  
  9. If 12 volts exists at the harness connector, proceed with the component check procedure.
  10.  

Component Check


Click image to see an enlarged view

Fig. Connect the meter positive lead to terminal 4 and the negative lead to terminal 2 of the control unit harness connector



Click image to see an enlarged view

Fig. Use a jumper wire to touch terminal 25 to ground

Before testing, visually inspect all components of the system. Replace any noticeably damaged parts. Be sure to check the ignition coil and replace if it is leaking fluid.

  1. Turn the ignition to the OFF position. Reconnect the control unit harness.
  2.  
  3. Unplug the harness connector from the Digifant control unit. Using a digital multimeter switched to the 20V range, connect the meter positive lead to terminal 15 and the negative lead to terminal 1 of the ignition coil. If necessary, unplug the wiring from ignition coil terminal 1, then reconnect it so that only the wire to the Hall control unit is engaged.
  4.  
  5. Turn the ignition switch to the ON position. The meter must read a 2 volt minimum, then drop to 0 volts after 1-2 seconds. If not, replace the Hall control unit.
  6.  
  7. Using a jumper wire, briefly touch terminal 25 of the Digifant control unit harness connector to ground. Displayed voltage must rise briefly to a 2 volt minimum.
  8.  
  9. Turn the ignition switch to the OFF position. Reconnect the control unit harness.
  10.  

REMOVAL & INSTALLATION



FOX

The ignition control unit is located under the instrument panel on the passenger side of the vehicle, below the ECM.

  1. Make sure the ignition key is in the OFF position.
  2.  
  3. Remove the rubber weather-strip seal from the firewall. Carefully pull the plastic drain tray from the cowling.
  4.  
  5. Unplug the connector from the ignition control unit.
  6.  
  7. Remove the screws securing the to the heat sink/bracket assembly.
  8.  
  9. Remove the ignition control unit control unit.
  10.  

To install:

  1. Clean the mating surface of the heat sink/bracket and the bottom of the ignition control unit. These surfaces must be free of any debris.
  2.  
  3. Spread an even coat of dielectric grease on the bottom of the ignition control unit (the bare metal side). The dielectric grease helps to make a better thermal connection between the ignition control unit and the heat sink.
  4.  
  5. Position the new ignition control unit on the heat sink/bracket, then tighten the screws until snug.
  6.  
  7. Engage the electrical connection.
  8.  

Digifant II

The ignition control unit is located in the cowling above the firewall in the engine compartment.

  1. Disconnect the negative battery cable.
  2.  
  3. Make sure the ignition key is in the OFF position.
  4.  
  5. Remove the rubber weather-strip seal from the firewall. Carefully pull the plastic drain tray from the cowling.
  6.  
  7. Unplug the connector from the ignition control unit.
  8.  
  9. Remove the screws securing the to the heat sink/bracket assembly.
  10.  
  11. Remove the ignition control unit control unit.
  12.  

To install:

  1. Clean the mating surface of the heat sink/bracket and the bottom of the ignition control unit. These surfaces must be free of any debris.
  2.  
  3. Spread an even coat of dielectric grease on the bottom of the ignition control unit (the bare metal side). The dielectric grease helps to make a better thermal connection between the ignition control unit and the heat sink.
  4.  
  5. Position the new ignition control unit on the heat sink/bracket, then tighten the screws until snug.
  6.  
  7. Engage the electrical connection.
  8.  
  9. Install the idle stabilizer or plastic cowling cover and weather-strip seal as applicable.
  10.  
  11. Connect the battery cable.
  12.  

 
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