For testing all models except the 1984 turbo, locate the inhibitor switch electrical connector next to the battery, identifiable by its eight attaching wires. Disconnect the connector and ensure the shift selector is in the Park position, then use an ohmmeter on terminals two and five to check for continuity. When the shifter is in Reverse, there should be no continuity between terminals two and five, while continuity should appear between terminals one and three. In Neutral, continuity will be lost between terminals one and three, and continuity will be present between terminals one and four. When the shifter is in Drive, continuity in terminals one and four will be lost. For the 1984 turbo model, locate the inhibitor switch electrical connector by its four attaching wires or trace the wire from the switch on the transmission. After disconnecting the connector, verify the shift selector is in Park and check continuity between terminals one and two. In Reverse, there should be no continuity at those terminals, with continuity shifting to terminals three and four. In Neutral, continuity will be lost between terminals three and four, while terminals one and two will show continuity. In Drive, continuity will be lost in all terminals. For adjustment, place the shifter in Neutral, raise the vehicle securely on jackstands, remove the inhibitor switch adjustment hold-down screw, and loosen the two adjustment bolts. Rotate the inhibitor switch until a 0.079 inch diameter wire fits into the hole left by the removed screw, then tighten the adjustment bolts and remove the wire before replacing the hold-down screw. Finally, repeat the ohmmeter tests, and if any fail, replace the inhibitor switch.