Factory security system problem

[jghall6]

The factory option security system started acting up on my 87 GN. The security light flashes all the time with the doors closed and unlocked. When the door is locked and closed the security light stays on all of the time and will not turn off. This is causing the battery a drain down. When I crank the car up the security light goes off. It's like the system is acting as if the door was open all of the time. Anyone know what the problem may be? Thanks.

 

[Raeban]

I don't use my system often so I am going from memory but my understanding of the factory system is that if the door is open and unlocked the light should flash, and if the door is open and locked the light should come on steady. When you close the locked door the light should then go out. When you turn the car to run you disarm the system so the light goes out.

As I see it the controller is seeing the action of locking and unlocking the door by changing from a flashing signal to a solid one, but is not seeing the door close so it doesn't turn the light off. Does this happen with both doors? One thing is for sure the theft deterrent on our cars is complex...

 

[jghall6]

Yes. It happens whether I lock or unlock both doors.

 

[markboss]

Check your trunk lock...It has a cable attached to the lock cylinder, it has probably not in adjustment..

 

[aminga]

The door pin switches have a connection to the alarm one of them is probably bad or disconnected

 

[jghall6]

Checked door pin switches and door/trunk locks. Continuity test were good on all wires. Had to disconnect harness from module under dash. Very difficult to get to. Where can I find another module? What is the part number? Thanks.

 

[salvageV6]

If one of the tan or blue wires for the door switches and tamper switches on the lock cylinders is shorted to ground it will also cause that problem.

I would think any of the used parts vendors could get you that module reasonable.

They rarely go bad but that is the last step in the troubleshooting process a new theft deterrent module.