Ponyboyt check you PM (ah crap I just noticed the "t" and I sent a PM to ponyboy). You (or who ever is ponyboy) have all the answers in there but since is no secret matter here is for everybody who needs it:
1. BOSE/Base HUs from '96+ are OBDII ('96 and older are OBDI).
2. BOSE HU from '96 and '97 have only Radio* and Tape + provision for 12 disk CD Changer. '98+ BOSE HU have RDS Radio, Tape, CD slot and provision for 6 and/or 12 Disk CD changer. *All domestic '96-'97 BOSE HU have non RDS radio. I have seen a '97 BOSE (tape only) export (Germany) BOSE HU with RDS radio.
3. BOSE HU of any year is not compatible with base HU and the other way around so if you are planing to swap between base and BOSE stop reading it won't work (trust me, forget about it!).
4. OBDI and OBDII HU (base or BOSE) are NOT interchangeable so if you have a '95 and older car you cannot upgrade (again stop reading is not going to work!)
5. ANY '96-'97 BOSE Cadillac (except '97+ Catera) can be retrofitted with a '98-'00 BOSE HU
6. You can also install a '96-'97 BOSE HU in a '98+ car (except Catera). I don't know why would you want that but it works and no VIN clear is required (is truly plug and play).
7. 5 and 6 (including VIN comment) applies also to base HU but consider 3 (can't swap between base and BOSE period).
8. '98+ HU (BOSE ore base) includes Theftlock. You cannot just swap a Theftlock HU between two cars* unless the VIN is blanked. *The cars can be ANY year '96+ (again we are NOT discussing Catera).
9. In the '96-'97 Seville, '96-'99 Deville and '96-'02 Eldorado the HU compares the VIN with the PCM, in the '98-'03 Seville and '00-'04 Deville the HU (same HU as in similar year Eldorado) compares the VIN with the DIM.
10. The "compare" VIN is post "Read VIN" command. Any '96+ Cadillac supports this "Read VIN" command.
11. A brand new* Theftlock enabled HU (i.e. '98+ model) has the VIN blank before installing it in the car. *Re-flashing the firmware in the HU = brand new HU. Unfortunately I don't know anybody having the firmware nor how to re-flash it (so forget about this idea, there is no battery in the non NAV BOSE HU, the firmware is written in the control chip RAM, non-volatile memory).
12. A HU with blank VIN accepts ANY VIN and locks on it. So at the plant you can put any HU in any car. But once connected to the data bus it locks* on that car VIN. As long as you have a brand new '98+ - never installed in a car - HU you can put it in any '96+ Cadillac (no VIN blanking required). *The theftlocked HU startup sequence is:
a) Send Read VIN command
b) Read reply (within a timeout period). If no reply jump to h)
c) If stored VIN is not blank jump to e)
d) Store received VIN
e) Compare stored VIN with received VIN, if match jump to g)
f) Post "THEFTLOCK ENABLED" message on the screen, issue Theftlock code (Bxxxx), jump to h)
g) Continue with the audio startup procedure (read driver's settings, select proper source, volume level, EQ settings, DSP...)
h) Read clock from PCM, enable audio mixer and chime circuit.
13. A '98+ BOSE HU always initiate the startup sequence when connected to power, or immediately after "Clear VIN" command, so it locks immediately on the VIN of the car where is installed.
14. A used HU has a VIN stored, to blank the VIN, the HU needs to be connected to a car data bus. This is done with a TechII tool witch address the HU with the command "Clear stored VIN". The TechII works with any OBDII car, you need to set up your car before using it to control various modules in the car. The most convenient way to set up the car in the TechII is based on VIN. This will set up the TechII to expect all the specifics (options) of that car. You can also set up manually the tool selecting year, model, options (but is the long way around and is prone to "setup" errors). Either way you set up the tool (refereed as build your car options into the TechII) VIN or manual you specify the year. TechII knows that a '96-'97 car has no Theftlock enabled HU thus IT WILL NOT PROVIDE YOU THE OPTION TO CLEAR VIN. But if you are smart you know that to blank (clean) the VIN the TechII communicates ONLY with the HU. So when you setup/build your car in the TechII you select '98+ for the year (i.e. either provide a VIN of a '98+ car or you manually select model/year...). This is where 99% of the technicians don't understand and will tell you it "doesn't work" (they build a '96 or '97 car in the TechII and then they try to communicate with a '98+ HU). Just think for a moment is not too difficult to understand :bighead:.
15. BOSE sound system includes in addition to the HU a RIM (for the '96-'97 Seville, '96-'99 Deville, '96-'02 Eldorado and individual speaker amplifiers) or an Amplifier (kind of a RIM+Individual amplifiers in the same case for the '98-'03 Seville and '00-'04 Deville).
16. Cars with RIM have one power antenna AM/FM (not related with the fact that it has a RIM, just coincidence). Cars with Amplifier have glass integrated antennas (one AM and one FM). The '98+ HU provides a "FM band select signal" in addition to the "Power antenna control". These cars have a separate "antenna" module powered by the "Power antenna control" wire while the "FM band select signal" is used to switch between AM and FM antenna. The cars with power antenna don't use the "FM band select signal".
17. A '96-'97 RIM is 100% compatible with a '98+ car (although the P# is different). Swapping a RIM (if for some reason you need to) does NOT require any VIN blanking. Swapping a PCM or a DIM in a car with a theftlocked HU requires reprogramming the VIN in the VIN in the new PCM or DIM (NOT in the HU).
18. If you need (according to 1 to 16) to clear your VIN, you need a TechII. A GM dealer will have one but 99% of the dealers will send you for a walk if you ask this to be done in a '96 or '97 car (they just don't know better). The charge for this (~3 min procedure) is between $0 to $100 (but 90% is around $50).
19. In order to perform a VIN blank to a dealer you are obligated to show a legal proof of replacement HU provenience. The paperwork should specify the seller contact information and the donor vehicle VIN. The dealer is NOT suppose to perform this procedure if is not convinced the replacement HU is purchased legal. The donor vehicle VIN is NOT actually required in the process but is required for the dealer to cross check the donor vehicle owner against the HU seller (should be the same person).
Here is the proof a '97 Seville STS with a '99 Eldorado HU.
To O.P. I haven't forgot about you, still planning to visit your cars but I am kind of in South Africa right now for the next 2 weeks, I will return shortly to Canada only to leave for a couple of weeks for US, so count on my visit late April.
1. BOSE/Base HUs from '96+ are OBDII ('96 and older are OBDI).
2. BOSE HU from '96 and '97 have only Radio* and Tape + provision for 12 disk CD Changer. '98+ BOSE HU have RDS Radio, Tape, CD slot and provision for 6 and/or 12 Disk CD changer. *All domestic '96-'97 BOSE HU have non RDS radio. I have seen a '97 BOSE (tape only) export (Germany) BOSE HU with RDS radio.
3. BOSE HU of any year is not compatible with base HU and the other way around so if you are planing to swap between base and BOSE stop reading it won't work (trust me, forget about it!).
4. OBDI and OBDII HU (base or BOSE) are NOT interchangeable so if you have a '95 and older car you cannot upgrade (again stop reading is not going to work!)
5. ANY '96-'97 BOSE Cadillac (except '97+ Catera) can be retrofitted with a '98-'00 BOSE HU
6. You can also install a '96-'97 BOSE HU in a '98+ car (except Catera). I don't know why would you want that but it works and no VIN clear is required (is truly plug and play).
7. 5 and 6 (including VIN comment) applies also to base HU but consider 3 (can't swap between base and BOSE period).
8. '98+ HU (BOSE ore base) includes Theftlock. You cannot just swap a Theftlock HU between two cars* unless the VIN is blanked. *The cars can be ANY year '96+ (again we are NOT discussing Catera).
9. In the '96-'97 Seville, '96-'99 Deville and '96-'02 Eldorado the HU compares the VIN with the PCM, in the '98-'03 Seville and '00-'04 Deville the HU (same HU as in similar year Eldorado) compares the VIN with the DIM.
10. The "compare" VIN is post "Read VIN" command. Any '96+ Cadillac supports this "Read VIN" command.
11. A brand new* Theftlock enabled HU (i.e. '98+ model) has the VIN blank before installing it in the car. *Re-flashing the firmware in the HU = brand new HU. Unfortunately I don't know anybody having the firmware nor how to re-flash it (so forget about this idea, there is no battery in the non NAV BOSE HU, the firmware is written in the control chip RAM, non-volatile memory).
12. A HU with blank VIN accepts ANY VIN and locks on it. So at the plant you can put any HU in any car. But once connected to the data bus it locks* on that car VIN. As long as you have a brand new '98+ - never installed in a car - HU you can put it in any '96+ Cadillac (no VIN blanking required). *The theftlocked HU startup sequence is:
a) Send Read VIN command
b) Read reply (within a timeout period). If no reply jump to h)
c) If stored VIN is not blank jump to e)
d) Store received VIN
e) Compare stored VIN with received VIN, if match jump to g)
f) Post "THEFTLOCK ENABLED" message on the screen, issue Theftlock code (Bxxxx), jump to h)
g) Continue with the audio startup procedure (read driver's settings, select proper source, volume level, EQ settings, DSP...)
h) Read clock from PCM, enable audio mixer and chime circuit.
13. A '98+ BOSE HU always initiate the startup sequence when connected to power, or immediately after "Clear VIN" command, so it locks immediately on the VIN of the car where is installed.
14. A used HU has a VIN stored, to blank the VIN, the HU needs to be connected to a car data bus. This is done with a TechII tool witch address the HU with the command "Clear stored VIN". The TechII works with any OBDII car, you need to set up your car before using it to control various modules in the car. The most convenient way to set up the car in the TechII is based on VIN. This will set up the TechII to expect all the specifics (options) of that car. You can also set up manually the tool selecting year, model, options (but is the long way around and is prone to "setup" errors). Either way you set up the tool (refereed as build your car options into the TechII) VIN or manual you specify the year. TechII knows that a '96-'97 car has no Theftlock enabled HU thus IT WILL NOT PROVIDE YOU THE OPTION TO CLEAR VIN. But if you are smart you know that to blank (clean) the VIN the TechII communicates ONLY with the HU. So when you setup/build your car in the TechII you select '98+ for the year (i.e. either provide a VIN of a '98+ car or you manually select model/year...). This is where 99% of the technicians don't understand and will tell you it "doesn't work" (they build a '96 or '97 car in the TechII and then they try to communicate with a '98+ HU). Just think for a moment is not too difficult to understand :bighead:.
15. BOSE sound system includes in addition to the HU a RIM (for the '96-'97 Seville, '96-'99 Deville, '96-'02 Eldorado and individual speaker amplifiers) or an Amplifier (kind of a RIM+Individual amplifiers in the same case for the '98-'03 Seville and '00-'04 Deville).
16. Cars with RIM have one power antenna AM/FM (not related with the fact that it has a RIM, just coincidence). Cars with Amplifier have glass integrated antennas (one AM and one FM). The '98+ HU provides a "FM band select signal" in addition to the "Power antenna control". These cars have a separate "antenna" module powered by the "Power antenna control" wire while the "FM band select signal" is used to switch between AM and FM antenna. The cars with power antenna don't use the "FM band select signal".
17. A '96-'97 RIM is 100% compatible with a '98+ car (although the P# is different). Swapping a RIM (if for some reason you need to) does NOT require any VIN blanking. Swapping a PCM or a DIM in a car with a theftlocked HU requires reprogramming the VIN in the VIN in the new PCM or DIM (NOT in the HU).
18. If you need (according to 1 to 16) to clear your VIN, you need a TechII. A GM dealer will have one but 99% of the dealers will send you for a walk if you ask this to be done in a '96 or '97 car (they just don't know better). The charge for this (~3 min procedure) is between $0 to $100 (but 90% is around $50).
19. In order to perform a VIN blank to a dealer you are obligated to show a legal proof of replacement HU provenience. The paperwork should specify the seller contact information and the donor vehicle VIN. The dealer is NOT suppose to perform this procedure if is not convinced the replacement HU is purchased legal. The donor vehicle VIN is NOT actually required in the process but is required for the dealer to cross check the donor vehicle owner against the HU seller (should be the same person).
Here is the proof a '97 Seville STS with a '99 Eldorado HU.

To O.P. I haven't forgot about you, still planning to visit your cars but I am kind of in South Africa right now for the next 2 weeks, I will return shortly to Canada only to leave for a couple of weeks for US, so count on my visit late April.