Component Tests and General Diagnostics

1987 Chevrolet Chevette L4-98 1.6LSECTION Component Tests and General Diagnostics

Fig. 4 Servo diagnostic chart. Part 1 of 2:




Fig. 4 Servo diagnostic chart. Part 2 of 2:





SERVO TEST
Refer to Fig. 4 to check servo and related wiring.



Fig. 5 Set/Coast switch diagnostic chart:





SET/COAST SWITCH TEST
Refer to Fig. 5 to check set/coast switch and related wiring.



Fig. 6 On/Off/Resume/Accel switch diagnostic chart:





OFF/ON/RESUME/ACCEL SWITCH TEST
Refer to Fig. 6 to check Off/On/Resume/Accel switch and related wiring.



Fig. 7 Release switch diagnostic chart:





RELEASE SWITCH TEST
Refer to Fig. 7 to check cruise release switch and related wiring.



Fig. 8 Speed sensor diagnostic chart:





SPEED SENSOR TEST
Refer to Fig. 8 to check speed sensor and related wiring.



Fig. 9 Mode control continuity test:





MODE CONTROL ASSEMBLY
1. Disconnect mode control electrical connector from main harness connector at base of steering column.
2. Test continuity between switch connector terminals using an ohmmeter.
3. If continuity is not as shown in Fig. 9, switch is defective.
4. Check continuity between each switch connector terminal and ground. If meter indicates continuity, check for pinched switch harness in steering column mast jacket.



RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.