I just replaced the clutch and timing belt in my Corolla 4WD wagon AE95. Everything's fine except the reversing light won't work! Checked the switch, the connector, the bulb, socket, etc. Peeled back the sleeving on the loom next to the switch in case I had damaged it while manhandling the gearbox in and out - no damage, everything seems okay but the reversing light still won't work!! Any suggestions?