W Sprint/Caballero V6-262 4.3L (1986)
Wiring Diagram For Chart C-1A - Park/Neutral Switch Diagnosis
CHART C-1A - PARK/NEUTRAL SWITCH (AUTO TRANS. ONLY
Circuit Description:
The Park/Neutral Switch is closed to ground in Park or Neutral and open in Drive ranges. The ECM supplies 12 volts through an internal resistor to CKT
434 and senses that the switch is closed when the voltage at terminal B10 drops to less than 1 volt
Test Description:
1.
Checks for switch closing in the P/N position. This is indicated by low voltage on CKT 434.
2.
Checks to see that voltage increases in Drive or Reverse range.
3.
Checks for faulty wiring to ECM or faulty ECM itself. If voltage is present, it means wiring and ECM are OK.
