W 250 Pickup V8-360 5.9L VIN I (1987)
Speed Control Servo: Testing and Inspection
Ensure servo is properly grounded before performing following test.
Fig. 83 Servo Terminal Electrical Connections
1983-87 REAR WHEEL DRIVE MODELS
1. Connect a suitable test lamp between yellow wire and ground then proceed as follows:
a. Place speed control switch and ignition switch in "On" position. Test lamp should illuminate.
b. Depress "Set" button. Test lamp should go out and a clicking noise should be heard at servo.
c. Release "Set" button. Test light should illuminate and another click should be heard at servo.
d. If test results are not satisfactory, possible causes may be a blown fuse, faulty wiring or defective speed control switch or servo.
2. Connect a suitable test lamp between white wire and ground, then proceed as follows:
a. Place speed control switch and ignition switch in "On" position. Test lamp should be off.
b. Depress "Set" button. Test lamp should illuminate.
c. If test results are not satisfactory, possible causes may be faulty wiring or defective speed control switch.
3. Connect a suitable test lamp between dark blue wire and ground, then proceed as follows:
a. Place speed control switch and ignition switch in "On" position. Test lamp should illuminate.
b. If test result is not satisfactory, possible causes may be faulty wiring or defective brake, clutch, or speed control switches.