you can start with the fuse. Underhood fuse/relay box on passenger side of engine compartment near the strut tower
Fuse 2 (15A) - 12V all the time
Make sure that the contacts are not corroded etc. If the fuses are okay, check the wiring harness. Make sure the plugs are connected properly and that there is no corrosion in between. Last but not least, you can check your light switch with a multimeter and see if it has intermittent faults. My gut feeling is that it is your light switch that is failing.
IF YOU HAVE AIRBAGS, GET SOMEBODY WHO HAS DONE THIS BEFORE. OTHERWISE THIS DEVICE COULD EITHER FAIL OR GET DEPLOYED.
Courtesy of Autozone ;-)
All SRS wire harnesses are covered with a yellow insulation. Read the
SRS precautions found in this section and install the short connectors
1. Disconnect the negative battery cable and disable the SRS system.
2. Remove the upper and lower steering column covers.
3. Disconnect the 4-pin and 7-pin connectors from the switch.
4. Remove the switch retaining screws and slide the switch from its
5. Install the new switch in position and connect the electrical leads.
6. Install the upper and lower steering column covers.
7. Disconnect the short connectors and connect the negative and
positive battery cable.
This should be for information only if you have not done this type of work before. Anytime you are messing with the safety of others, let the experts do it.