The No. 1829 light used in the 5P7277 Voltage Tester is not in the Caterpillar parts system. Other lights are available from Caterpillar for replacement of the No. 1829 Light.
It is Caterpillar's recommendation that an 8D1429 Bulb (No. 1820) be used as a replacement for the No. 1829 Light. The 8D1429 Bulb uses a little more current than the No. 1829 Light, but there is no difference in its performance.
The 5D1708 Bulb also can be used as a replacement for the No. 1829 Light, but it uses more than two times the amount of current the No. 1829 Light uses. The 5D1708 Bulb must be used only if an 8D1429 Bulb is not available.