1985 C4. security light, door lock problems
Thread Starter
5th Gear
Joined: Aug 2011
Posts: 5
Likes: 0
From: columbus ohio
1985 C4. security light, door lock problems
Does anyone know off hand if I unlock/lock the doors from the outside, with the key, should the other door lock or unlock too? My car does not, and I'm trying to figure out why I cannot clear the security light by locking the door with the key. The doors both lock and unlock together when using the interior switches. Looking at the schematic I might need to replace the door lock relay, or maybe a new theft module or both door lock switches? Any suggestions on testing to theft module or door lock relay will help, where is the door lock relay?
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
I know its a feature on newer cars where you stick the key in the locked door and turn it once, the drivers opens, and turn it again, the whole car unlocks. I don't believe it was a feature on the 85. Not sure about later years. Mine has never done it, but my car is not a tip top shape 85 either.
I had security light issues as well, the security light would stay on constantly and would actually drain my battery overnight. I am working on removing the anti theft module. Had an issue where i would lock the doors from the inside with the power locks, close the door and the alarm would go off.
If someone really wanted to steal it, a car alarm isn't going to stop them.
I had security light issues as well, the security light would stay on constantly and would actually drain my battery overnight. I am working on removing the anti theft module. Had an issue where i would lock the doors from the inside with the power locks, close the door and the alarm would go off.
If someone really wanted to steal it, a car alarm isn't going to stop them.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The key will only unlock the door it's put into. It's strictly a mechanical link to the lock mechanism. The lock/unlock switches will lock and unlock both doors at the same time. There is a switch on the door key cylinder that disarms the alarm when you unlock the car with the key.
It sounds like your system is working normally except for the Security light. You need to look at the antitheft module and the wiring between it and the Security light.
Another thing that will light the Security light is an open door. If your door jamb switch isn't working correctly it can fail to shut off the Security light when the door is closed.
This could be Pwnage's problem also. The alarm will go off if you don't close the door within some time (I think it's 45 seconds). If the door jamb switch is not working the alarm system thinks the door is open.
It sounds like your system is working normally except for the Security light. You need to look at the antitheft module and the wiring between it and the Security light.
Another thing that will light the Security light is an open door. If your door jamb switch isn't working correctly it can fail to shut off the Security light when the door is closed.
This could be Pwnage's problem also. The alarm will go off if you don't close the door within some time (I think it's 45 seconds). If the door jamb switch is not working the alarm system thinks the door is open.
Thread Starter
5th Gear
Joined: Aug 2011
Posts: 5
Likes: 0
From: columbus ohio
OK, thanks for the info. Before I tear apart the interior to find the theft module, is it located in the center behind where the security light is or is up underneath the the passenger side?
By the way I cannot turn off the security system with the key in either door, tried like 100 times lock/unlock etc etc.. Is there a FUSE IN THE THEFT DETERRENT MODULE THAT MIGHT BE BLOWN?
By the way I cannot turn off the security system with the key in either door, tried like 100 times lock/unlock etc etc.. Is there a FUSE IN THE THEFT DETERRENT MODULE THAT MIGHT BE BLOWN?
Thread Starter
5th Gear
Joined: Aug 2011
Posts: 5
Likes: 0
From: columbus ohio
OK, thanks for the advice from everybody so far!! What I found was a stuck door ajar switch on the drivers door. Do you suppose that the system wouldn't reset if the car thought the door was never opened. I hope so, I had to pry the switch out now it shows door ajar on the messages, and knock on wood no horn or security light has occured.
wait and see..........
wait and see..........
