A clicking noise may be noted from the turn signal flasher after the turn signals are switched off. This is commonly cause by a faulty turn signal switch which will require replacement.Google+
Car Problem Reports
Chevrolet Silverado 1500 Turn Signal Switch May Fail and Cause Clicking Noise
Chevrolet Silverado 1500 Problem
Average Mileage: 145,688 mi (123,000 mi - 180,000 mi)
Visitor, 2002 Chevrolet Silverado 1500, 180,000 mi
same as the other folks
Visitor, 1999 Chevrolet Silverado 1500, 157,000 mi
"clicker" comes on by itself. stops if I depress the brake.
Most annoying, turn up radio.
Visitor, 2000 Chevrolet Silverado 1500, 123,000 mi
Turn signal clicking noise continues on its own without lights being activited.