2002 gmc sierra security problem

hi: hope somebody can help me out with this problem. i'm installing a remote starter on a 2002 gmc sierra and i tryed to use a bypass ,and doesn't work fine . so i decide to use one of the data by=pass kit .and now it start but the security light on the panel is on at all time.what can i do to solve this? the customer told me not to disconnect the battery for a long time because when he bought the truck the guys at the dealer told him that he could damage some sensor ( wich sound strange to me) but anyway. any help will be appreciated.

ok seems easy to do. so actually what i'm doing here is put ground to the bypass after the remote start the engine? it's some kind of reset? i'll try it and see if works. thanx for the advice . it is true that if you leave the key on to the run position for a while  will reset the anti theft system?

i' still have the problem in the truck ,if somebody knows another solution to this issue please let me know asap. thanx . if i don't get it solved i must send the truck to the dealer and i really don't want to , cause you 'all know that is expensive.