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Speed Sensor Check

NOTE: This is an alternate test when an oscilloscope is not available.
  1. Secure a Fresnel lens front LED from an electronics store or use Special Test Unit (171 919 061B ). Connect a 220 ohm-1/4 watt resistor in series with one of the LED terminals.
  2. Connect positive LED test lead to terminal 8 of CU harness connector. Connect negative LED test lead to terminal 27 of same connector. DO NOT  start engine, but operate starter. LED will flicker dimly if speed sensor is sending a signal.
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