the f23a1 vtec engagement is between 2300 and 3500 ish RPM's dependng on throttle position and a few other factors. which is why this may confuse you Mariam Disuja as the f23 vtec is totally different from the r18. the indicator light simply tells you when power is being sent to the vtec...
Today i decided to do the simple Vtec indicator light mod. i used this write up--
http://6thgenaccord.com/forums/showthread.php?t=6831&highlight=vtec+indicator+light
i made a few slight changes like instead of splicing the vtec wire and taping, i used a splice in connector. its alot...