Dis-arm wire issue

hi, we have an odd issue that after testing everything we still can't figure it out. On an '02 corvette, the dis-arm wire should be a light green in the BCM. We tested this and verified that this wire pulses ground when the key is turned in the door lock. We connected the alarms dis-arm wire to this wire. However, if you sit inside the car, arm both alarms, then open a door triggering both alarms, you should be able to shut off BOTH alarms by dis-arming the after market alarm. the after market alarm dis-arms but the factory alarm just keeps going. we even verified AT the green wire in the BCM that it does in fact receive a ground pulse when the after market alarm is disarmed. whats the deal? thanks, john

i would guess that the only way you have to disarm the factory alarm upon triggering it is to use the key in the door. if you may need to go directly to this wire coming from the key tumbler inside the door itself. good luck!

You may have to use a relay and get a solid ground to the bcm. That would be my guess, since you have verified you have the right wire. Try that and see what happens. DanDan

I actually tried putting a solid ground right to the green wire at the BCM while the factory alarm was going off...and nothing. Yet this is the only light green wire at the BCM that flashes ground when the door is unlocked with the key so it has to be the right wire. i already tested the wires coming off the door lock inside the door. there are four possible wires (one of them happens to be light green) but putting an ohm meter on them showed GROUND at all times??? i still wanted to test that green wire coming off the door cuz i had a feeling that was the right wire. so i set off the factory alarm again, put a ground on that light green wire coming off the lock and what do you know...the alarm stopped. this car is really annoying because not only does the light green wire read ground AT ALL TIMES but so do BOTH door triggers at each door. whats weird is i said to hell with it, wired them up to the alarm anyway and all 3 of these wires work perfectly. you would think that since the door triggers read ground at all times then the after market alarm would think the doors are open when you armed it and complained about it...but it didnt? atleast its fixed! thanks guys, john

The disarm wire from the door key cylinder doesn't go to the BCM. It only goes from the key cylinder to the door module inside the door. From there, the signal is data to the BCM. If you lock the doors with the key and test the light green wire in the door you will find that it isn't grounded. Most newer GM vehicles no longer use a disarm wire to the BCM. They mostly have gone to using door modules and data communication. sparky