Randomly probing wires with a test light won't tell you anything.
WIPERS INOPERATIVE
Turn ignition on and check for battery voltage at wiper motor terminal 2, Fig. 5, using a test lamp.
If lamp fails to light, proceed as follows:
Check wiper system fuse and replace if needed.
If fuse blows again, disconnect electrical connector to motor and replace fuse.
If fuse does not blow with harness disconnected, replace wiper motor.
If fuses continue to blow with harness disconnected, or if fuse was satisfactory in step ``a,'' repair feed circuit to wiper motor.
If lamp lights in step 1, check for battery voltage at motor terminal 1.
If lamp fails to light, check terminal board connections and repair as needed. If connections are satisfactory, motor is defective.
Place wiper switch in low position, disconnect electrical connector to gear box relay and connect test lamp between terminals 1 and 2 in connector.
If lamp fails to light, check continuity of wiring between motor and switch, switch continuity and ground, and repair as needed.
If lamp lights in step 5, place wiper switch in high position, disconnect electrical connector to pulse timer and connect test lamp between terminal 6 and timer connector and terminal 2 in gearbox relay connector.
If lamp fails to light, check continuity of wiring between motor and switch, switch continuity, and repair as needed.
If lamp lights in step 7, motor is defective.