Passlock- C4 1990 convertible
Thread Starter
4th Gear
Joined: Jan 2013
Posts: 4
Likes: 0
Passlock- C4 1990 convertible
I was having probs with alarm going off. I went into both door panels and unplugged both passlock pigtails, now my power locks dont work. What can I do to bypass the passlock system? Is the VATS influnced by this or is it a seperate system, not affecting each other. I have a VATS bypass on standby if I need to use it. 1990 Corvette Convertible
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
The factory anti theft system has two separate parts to it.
The passkey is the part that reads the key pellet resistance of
the ignition key.
If it doesn't compare with the resistance the CCM was
programmed for the starter motor and fuel injector pulsing are disabled.
The factory alarm is set by using the power door lock switch.
With the door open you use the power door lock switch to lock the doors. When the doors are closed the alarm is set. The system then monitors the door ajar switches mounted on the back edge of the doors. On a coupe the hatch ajar switch is also monitored. If the alarm is triggered the horn is pulsed. To shut the alarm off you use the door key.
So if you set the alarm and it triggers for no reason the problem is most likely one of the door ajar switches.
The passkey is the part that reads the key pellet resistance of
the ignition key.
If it doesn't compare with the resistance the CCM was
programmed for the starter motor and fuel injector pulsing are disabled.
The factory alarm is set by using the power door lock switch.
With the door open you use the power door lock switch to lock the doors. When the doors are closed the alarm is set. The system then monitors the door ajar switches mounted on the back edge of the doors. On a coupe the hatch ajar switch is also monitored. If the alarm is triggered the horn is pulsed. To shut the alarm off you use the door key.
So if you set the alarm and it triggers for no reason the problem is most likely one of the door ajar switches.
Last edited by Hooked on Vettes; Jan 26, 2013 at 10:53 PM.
Thread Starter
4th Gear
Joined: Jan 2013
Posts: 4
Likes: 0
My door ajar switches are working. The dome lights come on and the engine runs fine. I just want to be able to bypass the door key switches. I unplugged the pig tails from inside the doors. Can a resistor be soldered in place?
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
A switch is mounted on the back of each door key cylinder. When you turn the key to unlock the door the switch sends a ground signal to turn the alarm off. The switch has a connector plug with two wires. A
Green wire and a Black/White wire.
Here's a thread with a picture of the door disarm switch. This switch
has no connection with the power door locks.
http://forums.corvetteforum.com/1580140972-post4.html
Green wire and a Black/White wire.
Here's a thread with a picture of the door disarm switch. This switch
has no connection with the power door locks.
http://forums.corvetteforum.com/1580140972-post4.html
Last edited by Hooked on Vettes; Jan 27, 2013 at 12:29 AM.
Melting Slicks
Joined: May 2007
Posts: 2,075
Likes: 109
From: Longmont Co
VATS is not the alarm. They are separate systems.
