Truck-Lite SS91253Y101 Turn Signal Switch Assembly (part number 91253Y101). This black heavy-duty turn signal switch controls commercial vehicle turn signals and interior hazard mechanisms. It features an Inside Diameter (I.D.) of 5.25", an Outside Diameter (O.D.) of 7.386", and a width of 1". It serves as a direct factory replacement for Terex / Advance mixer trucks and Thomas Built buses, and cross-references with part numbers 577.99006, 16033, 26958, 26958M, 49916A, and 61320816.