If the same neon bulb lights then the problem is in the second half of the set.
Easy way to check xmas lights.
Easy ways how to fix led christmas lights using a tester led and light keeper pro repair kit tool 16 http amzn to 1r0cgri link supports the channel led.
If the original neon bulb lights move halfway down the remaining part of the set and try again.
Then remove the middle bulb of the string and check it with the multimeter.
Open the sliding compartment door and remove the fuse s.
Christmas light testers the most convenient way to test for faulty bulbs in a light string is through the use of a light tester.
Either way you are testing 25 of the 50 bulbs without breaking into a sweat.
Then connect the second bulb to the socket in the middle of the string.
At first divide the number of lights into two distinct sections.
Check the fuse holiday lights usually have cartridge fuses in a small compartment in the cord plug behind a sliding door.
Light testers search for the point in the string where the voltage changes between a good bulb with current flowing and a problem area with minimal current.