Ford Escort/Lynx 1981-1990 Repair Guide

Idle Tracking Switch

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Testing

MCU Systems

See Figure 1

  1. Check that the idle tracking switch contacts are open when the switch is actuated (closed throttle) and that the contacts are closed when the switch is not actuated (part throttle).
  2.  
  3. If the switch contacts are open when the switch is actuated (closed throttle), the switch is functioning properly.
  4.  
  5. If the contacts are closed when the switch is not actuated (part throttle), proceed as follows:
    1. Turn the ignition key OFF .
    2.  
    3. Disconnect the module from the harness.
    4.  
    5. Use a Digital Volt Ohmmeter (DVOM) to measure the resistance between circuits 189 and 687 (refer to the accompanying illustration). The resistance should be between 280-380 ohms.
    6.  

  6.  
  7. If the resistance is not in range, replace the resistor and the switch.
  8.  



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Fig. Fig. 1: Idle tracking switch wiring schematic-MCU systems

 
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