Lost master key, Having issue with key relearn

[up2ng]

Hey guys, new to the forum and am looking for some help! First thing I will say is I have spent lots of time doing some research but still having some issues!

My issues at hand, Well I lost the one and only master key I have for my NBS 2007 Chevrolet Tahoe(foolish to only have one, I know). So I have gone to the dealership and purchased a new vin cut transponder key. Now I have read about a 30 minute key relearn procedure, with a solid illuminated security telltale. Unfortunately for me my telltale is in a flashing state. I have disconnect the battery and grounded the positive lead out. My dash says "service theft deterrent system" but my light will stay flashing. Ive let the vehicle sit with the ignition on with a battery charger for over 40 minutes to see if the light will even go out, but nothing. Just stays flashing.

Can anyone help me? I just want to get the telltale to stay solid so I can go and follow through with the key relearn procedure. Thanks in advance!!!

 

[BlackOh7on22s]

You turn the key forward for 10 minutes then check it, the light should be out. You do this same exact procedure 2 more times and then after the 3rd time turn the key off then start the truck and the key should be learned and be good after that

 

[BlackOh7on22s]

Basically turn key to run position w all the lights on and leave on for 10 mins, check for light to be off then turn key off and then back to run postion again and repeat once more after that if you get the procedure?

 

[up2ng]

Thank you for the quick response. I have tried that several times now, unfortunatly after 10 minutes my security light will not go out. I've even let it sit for a much longer period and still nothing. The light stays flashing and hasn't gone out once.