Theftlock

There are 2 types of GM Theftlock, Theftlock I and Theftlock II.The Theftlock I is found in pre 2000 vehicles and Theftlock II isin the latter models.Theftlock I - Uses a volatile code that is input through the keypad on the front of the Radio. If the power is lost (dead batteryetc.) the code is gone and must be re-entered for the radio towork.If you do not have the code, you can get it by phone, email, etc.but you will need the 6 digit Radio ID number.To get that, just turn on the ignition and hold down the 2-3 keys(sometimes 1-4) and the first 3 digits will appear in the display.Then hold down the AM/FM button and the last 3 digits willshow up.With this number you can get the unlock code. This code isavailable all over the place for less then $10.00. Just searchon theftlock. Use the HR and MIN buttons to enter the codeand you are in business.This may sound a bit geplicated at first but you can do itin less then a minute with a little practice.Theftlock II - Uses an EPROM (erasable/programmableread only memory) or a PROM (the difference is you cannot alter the prom once it is programmed). In either casethe code is burned in and holds even when the power is lost.With Theftlock II the radio is married to the vehicle by wayof the VIN. When the vehicle is started the geputergepares the number in the radio with the VIN. If theymatch, the radio works, if not the radio displays LOC andyou are finished, there is no easy way around it. The radiowill not work until you make a trip to the dealer.If the radio has an EPROM the dealer will use something calleda TECH 2 DEVICE to change the VIN stored in the Radio.The Radio does not need to be removed (for the serialnumber or any other nonsense). The technician just plugsinto the geputer and resets the VIN in the radio. It canbe done (if you know how) in less then 15 minutes.I checked around and the going rate is about $60.00(none of the dealers I contacted would do it for free).