Can't silence alarm or start after replacing battery
Thread Starter
8th Gear
Joined: Sep 2008
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Can't silence alarm or start after replacing battery
2000 C5 coupe 6 speed, battery died, replaced with new 78 series. When I connect the new battery the alarm sounds immediately, eventually silencing on its own after a short while. Unlocking the driver's door sets off the alarm, locking and unlocking with key does not reset it. Car will not start. Don't use or even have a remote fob, always used only the Passkey.
I bought the car used, so I don't know if there's an aftermarket alarm installed. So, bear with me (and don't laugh too much), what does the OEM alarm sound like? Just the horn, or is it a multi-tone? Mine is multi-tone, so if the OEM is just the horn I'll need to do some digging. Also, unlocking the driver's door should silence the OEM alarm, correct? Or is there another method?
FYI, car also has Lojack Early Warning, but I don't think that's involved.
Any ideas would be greatly appreciated and will save me from tearing the dash out to see if there's an aftermarket system hiding somewhere.
I bought the car used, so I don't know if there's an aftermarket alarm installed. So, bear with me (and don't laugh too much), what does the OEM alarm sound like? Just the horn, or is it a multi-tone? Mine is multi-tone, so if the OEM is just the horn I'll need to do some digging. Also, unlocking the driver's door should silence the OEM alarm, correct? Or is there another method?
FYI, car also has Lojack Early Warning, but I don't think that's involved.
Any ideas would be greatly appreciated and will save me from tearing the dash out to see if there's an aftermarket system hiding somewhere.
Last edited by i2ibud; Oct 1, 2009 at 12:23 AM.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
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From: Forney Texas
Look around for a chrome toggle switch or a black push button switch. Connect your battery and flip or press the switch. A few aftermarket alarms had the switch built in to the LED assembly, so if you can't find the valet switch, try pushing on the LED. If you can't find the switch, you need to pull the underside of the dash and disconnect power from the alarm and close the starter circuit. Find the purple 10 gauge wire from the ignition switch. When they installed the alarm, they cut that wire and reconnected it through a relay to allow the alarm to open the starter circuit. remove their connection and restore the path on the starter wire to original and you'll be back in business. 
Thread Starter
8th Gear
Joined: Sep 2008
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Thanks, blownblue, I'll see what I can find a valet switch as you suggested. I'm going to install an iPod2Car anyway, so I'll have the dash apart and the radio out and I'll look for an alarm while I'm in there. I'm assuming that since there's a starter cutoff and a multi-tone alarm it's aftermarket - is that a good assumption?
Can anyone verify that the OEM theft deterrent uses only the horn for the audible alarm, not 6 tones with a siren, beep, etc? This is the first Corvette I've owned, and I can't find a description of the sound of the C5 OEM alarm anywhere. TIA.
Can anyone verify that the OEM theft deterrent uses only the horn for the audible alarm, not 6 tones with a siren, beep, etc? This is the first Corvette I've owned, and I can't find a description of the sound of the C5 OEM alarm anywhere. TIA.
Thread Starter
8th Gear
Joined: Sep 2008
Posts: 8
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Thanks for all of the help with this, you guys nailed it. I installed an iPod2Car today, and in taking the dash apart I found a Code Alarm system... the valet button was just taped behind the knee panel under the steering wheel. Problem solved.
