Hi!

The dealer tells me that junk yard radios will not work as they go into
theft mode as soon as you remove them from the vehicle. If that is
so why didn't my original radio do this when I removed it and reinstalled it
numerous times?

The dealer doesn't know what they are talking about, and they are
mixing things up. Collectively, GM refers to all of these systems as
TheftLock (except the earliest one, which is called Delco Loc II.) I
don't know if there was a Delco Loc I or not.

Early Delco Loc and TheftLock radios could or did have a code in place
that would have to be entered if the radio lost power.

The later radios, such as your 2000 model use a different approach. A
small EEPROM on the board holds a copy of the VIN (along with other
parameters) and this is checked over the CAN bus with what is stored
in another computer. If the two do not match--or if there is no
response from the CAN bus, as there would not be if you were bench
testing the radio--the unit will not power up or display anything
other than the clock.

There are a few solutions:

1. Install an aftermarket radio.
2. Pay the dealership what they want to program the new radio.
3. Open the radio up, locate the EEPROM that stores the VIN and
disconnect it. This will cause the radio to report things such as "CAL
error" and complain, but it will work normally otherwise. This is
somewhat difficult because GM house-numbered *everything* in these
radios, even common parts like the EEPROM.

Some parts have their normal numbers, but many do not. There are some
equivalency tables on the web that you might find.

On many of these, pushing several of the front buttons at once will
result in the radio powering up and running despite TheftLock. I
suspect this is a diagnostic test mode, though the set operates
normally. However, late model (2006 and later for sure) radios have a
time-out, after which they will shut off. The one from my 2003 S-10
played for hours this way, so I don't think it does.

William