Remove the steering column covers.
Disconnect the 12P connector (A) from the combination light switch (B).
Turn the steering wheel to access the combination light switch screws (C).
Remove the two screws, then slide out the combination light switch.
Inspect the connector terminals to be sure they are all making good contact.
If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
If the terminals look OK, check for continuity between the terminals in each switch position according to the tables.
If all the continuity is not as specified, remove the two screws and replace the switch.
Install the parts in the reverse order of removal.