How Unlock A GM Delco Radio

[aerodonamic]

Type in how to unlock a gm delco radio on google, a video will come on telling you what to do, it is 5mins. long, I went straight out to my car hooked up a locked radio , went thru the procedures , radio unlocked and played ok. aerodon!!!

[Fierofool]

We have the procedure in the Tech Q & A.  I've updated it with the additional codes given in the video.  Here's the video Aerodon was talking about.

http://www.youtube.com/watch?v=1AVQZk8-qs4

[Alfa Seltzer]

Many GM Class II (data turn on) radios can be converted to work in older vehicles as well. I've done as late as 2004/2005 radios in older vehicles without issue.

Assuming You are looking from the back of the radio:

Pop the bottom cover off (no tools needed)

If equipped with cassette the mech may need to be removed (2-3 small bolts, 5.5mm on top of cassette assembly)

Behind the volume knob there will be two 8 pin chips (top right corner of Main PCB). These will often be encased in hot glue (easily removed with a pick). The one you want is the one located on the left if looking from the back of the radio.
 
Lift pin #8 (Bottom right hand pin if looking from rear of radio) of the chip on the left. This is the EEPROM that stores the VIN info for the radio.

Most GM Class II radios have both circuitry to turn on via data and via STD wiring (ie ign/constant/etc). Many will now switch over to turning on over standard wiring and work in any vehicle but display CAL ERROR briefly when first turned on.

Earlier may work (IE 99+) but seem to be hit and miss. I've had the best luck with 2002-2005.

Casette and CD mechs look to be interchangeable over a broad range of years. It is not uncommon for the CD Mech to be jammed or broken so grab a spare if Junkyard hunting.

[Raydar]

Behind the volume knob there will be two 8 pin chips (top right corner of Main PCB). These will often be encased in hot glue (easily removed with a pick). The one you want is the one located on the left if looking from the back of the radio.
 
Lift pin #8 (Bottom right hand pin if looking from rear of radio) of the chip on the left. This is the EEPROM that stores the VIN info for the radio.
...

From your description, it sounds like the chips are "through hole" mounted, instead of SMD (surface mount.)
Is that correct?

Have you had any issues with the radios not retaining clock or station settings after they are powered off?
Seems like I remember hearing about some "gotchas" associated with this mod, but it's been a while, so I'm not sure.
But in any event, if you've done this successfully, I certainly can't argue.
Thanks for sharing.

[Alfa Seltzer]

The IC's are SMD.

Some radios quit working when its done. On the ones that do work (50/50 usually) I haven't seen any issues besides the 'CAL ERROR' message being displayed.

Clock/Settings were retained on the ones I tried.