What was found
AT FL280, LE AMBER LIGHT ILLUMINATED (WING ANTI-ICE ON). NO ROLL OR DIRECTIONAL CENTRAL PROBLEM NOTED. NR 2 FLAP ON FE PNL L AMBER. SLOWED DOWN TO 230 KTS, CLOSED WING ANTI-ICE. LIGHT STAYED ON, RECEIVED QRH. DID NOT CHANGE CONFIG. DESCENDED T0 200 DECLARED EMERG. AFTER REDUCED PWR AND 240 FL LIGHT WON`T GO OUT KEPT POWER REDUCED. SUSPECT BLEED AIR LEAK. WING ANTI-ICE DUCTING ON THE LT SIDE LEAK CHECKED AS PER B727-100 AMM 30-13- 000-5 AND NO LEAKS FOUND. L/E POSITION INDICATING HARNESS INSPECTED AND NO DEFECTS FOUND. L/E FLAP POSITION INDICATING SWITCH REMOVED AND REPLACED PER B727-100 AMM 27-82-001-4 - PRECAUTIONARY. COULD NOT DUPLICATE THE FAULT, CHECKS SERVICEABLE.