Kubota RTV-X1140 Turn Signal Bulb Size

Additional Notes

• The Kubota RTV-X1140 rear turn signal uses two distinct bulb types across its model years: the P21W for 2016 and 2018, and the P21/5W for 2017.
• The P21W is a single-filament bulb operating at 12V and 21W, built to the ECE standard used in Europe and worldwide. It uses a BA15s bayonet base, which has a single contact pin at the base.
• The P21/5W is a dual-filament bulb operating at 12V with a primary filament rated at 21W and a secondary filament rated at 5W. It follows the same ECE standard but uses a BAY15d bayonet base, which has two offset pins to prevent incorrect insertion.
• The BA15s and BAY15d bases are physically incompatible with each other. The offset pin arrangement on the BAY15d base means a P21/5W bulb cannot seat correctly in a socket designed for the single-pin BA15s base, and vice versa.
• Because the 2017 model year uses the P21/5W while the 2016 and 2018 model years use the P21W, the rear turn signal socket configuration for the 2017 Kubota RTV-X1140 differs from the adjacent model years.
• The dual-filament design of the P21/5W, as fitted to the 2017 model, allows one bulb to serve two lighting functions simultaneously, such as a turn signal and a tail or parking light, within a single housing.
• The single-filament P21W, as fitted to the 2016 and 2018 models, serves only one lighting function per bulb, meaning a separate bulb would be required for any additional function in the same lamp assembly.