there's more to a touch switch than a diode. if we had a bit more information about the light, like manufacturer, model number, and a better description of what's wrong with it (is it on all the time or off all the time, or does it randomly turn on or off?)
i have check the diode and found one bad and i replace it but as soon as i change it i test it an the out put to battery was 9volt but not quite long it went back to 119volt and this time the diode are all okey
i think that there's a language barrier here, and online translation scripts always seem to choke with technical and engineering terminology.
i'll give this one more try, maybe we can get an idea what the OP is having trouble with.
1) who made the lamp?
2) what is it's model number?
3) what is it doing that is not normal?
4) can you show us pictures of the circuit board?
5) does the light run off of AC power from the wall outlet, or does it use batteries?