GM RADIO theftlock

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n2knc
Posts: 193
Joined: Sat Dec 13, 2003 8:01 pm

GM RADIO theftlock

Post by n2knc »

Does any one know a way to keep power going to your factory radio while disconnecting the battery terms ?im putting a high power radio in the car and need to go direct to the battery. once the radio has lost the power the radio will go in to LOC mode,and i dont want to have to have it unlocked or pay some stupid free to bring it back to life

an idea i had was to take a jump pack turn key on and back feed power thru the cig plug.
will this work?

any one have any ideas or has any one done any installs on gm cars and know any way around this?

Dave
N2KNC
High_order1
Posts: 210
Joined: Sun Oct 13, 2002 10:39 am

Re: GM RADIO theftlock

Post by High_order1 »

You can unlock the radio most times yourself. You use one of the knobs like a vault combo dial, and punch in part of the VIN, if I recall correctly, and a sequence of buttons, and it unlocks it. I can look for the doc on how to do it, if you can't find it via Google. I *think* it may even be in the owners' manual.

PS - it DOES have to be hooked into a car with a matching VIN. Otherwise, that's something a dealership or someone with an OBD tool has to fix.

PPS - some people make a doodad that lets you plug a 9v battery into the cigarette plug to provide memory power, but I've never heard of anyone using it for what you are trying to do. Potentially (pun intended), it could also work.


-Shawn
N0SIH
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Joined: Sun Apr 13, 2008 4:15 pm
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Re: GM RADIO theftlock

Post by N0SIH »

Don't know about brand new (2008) GM vehicles but usually a theftlock radio has an LED that will blink when armed and Ignition off. If the LED is not blinking then nobody has programmed the arm code into it and the battery can safely be disconnected. The 9 volt battery on a cig lighter plug will hold enough voltage to keep the memory active. If a radio were to be keyed to the proper VIN only how is it that salvage yards can sell them all day long without effect? The arming sequence is most always in the owners manuals as well. 73 de Jeff/N0SIH
2-Moxy, 2 Maxar-80, 2 HT-50, 2 Maxtrac VHF, 3 SP-50, 2 P110, 1 GM-300,1 M-1225,
12 M-100, 10 MTX-HT,1 STX-HT, 1 Mostar, 1 Flexar repeater on UHF ham, 1 GR-300 UHF on ham, 1 GR-500 on VHF, 6 P-200 HT. Oh and a couple of crates of Micor junk too.
motorola_otaku
Posts: 1854
Joined: Tue Jan 13, 2004 7:03 am

Re: GM RADIO theftlock

Post by motorola_otaku »

He's in an older car using an older GM radio if it goes into "LOC" when he disconnects power. New GM factory heads (or the ones they put into 9c1 Impalas, at least) will sit just fine without power for years, and only lock up if you try installing them in a different car whereupon they see the VIN mismatch. Only way around that particular issue is with a GM TECH II tool.

Older versions can be unlocked from the front. 10 seconds in Google yielded this:
Ok, I have an active dealer code figured out. You're going to need to take a pen and paper with you out to the car.


1) Go out to your car, and put the key to the 'on' position (not run). When the radio turns on, press and hold #2 and #3. After about ten seconds, three numbers will appear on the screen. Take your time and write these down.

2) After you have the first three numbers, press and release the AM/FM button. Three more numbers will appear on the screen. Write these down.

3) With your new-found 6-digit code, go inside and call 1-800-537-5140. It's just an electronic answering machine. Once the guy finishes talking, press 202108, followed by the *Asterisk* button (not pound).

4) He'll then tell you to enter in your 4- or 6-digit code, followed by the star/asterisk again. So, type in the numbers you got out of your radio, and hit star/asterisk.

5) He'll then tell you your 4-digit unlock code. Write it down.


Now you can go back out to your car, press and release the "HR" (hour) button until it flashes, and enter in the first two digits of your 4-digit code. Then press the MIN (minute) button and enter the last two digits. [For instance, if my code was the number "1848", I'd press the HR button 18 times and the MIN button 48 times]. When you're done, hit AM/FM. The radio is now unlocked.


To turn off Theftlock so you don't have to repeat this process the next power loss, just repeat the last step -- pressing HR and MIN to re-enter the code. When it's done and you hit AM/FM, a blank set of three hyphens ("---") will appear on the screen. You've disabled Theftlock.
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