Red, Amber or Green Payload Light Does Not Illuminate The payload lights only illuminate when the brake lock is applied. If all the load lights are not working, be sure to troubleshoot the light control relay, refer to “Payload Lights Won't Illuminate”. The most common reason for a payload light not working is a burned out bulb. Replace burned out bulbs with Komatsu's high durability replacement lights. Komatsu is also currently working on Light Emitting Diode (LED) replacement lights with significantly longer life. Check with your distributor for availability. M20007.2 3/02 Payload Meter II™ Troubleshooting M20-39