Security system issues and locks cycling (1 Viewer)

[Brutherb]

99 LC, new owner. If I put my key in either the drivers or passengers door the door unlocks but it sets the alarm off.

as well randomlyyou can hear the locks trying to lock the doors. It doesn’t unlock themyou can just hear them cycling.

I have read that the rear hatch wiring can be an issue. So I have the rear panel off and trying to trace down the problem, I have heard it can be the body control module.

lastly if I stick the key in the hatch it does nothing, doesn’t lock or unlock anything, so that is why I am guessing that is where the issue lies. I can see the 2 wires that attach to the back of the lock cyclinder. Just not sure where to start.

if I pull the lock out and put a volt meter on the terminals when Iturn the key should I get a reading.

 

[gregnash]

Same here and known issue with lock actuator motors when they are on their way out. There is a large "Door Lock Actuator" thread that will tell you what you need to do and which model motor you should buy for your year vehicle.

As for the lock itself being powered, no. There is a motor assembly that drives the lock cylinder via cables. Then there is a ring sensor around the lock cylinder that tells the immobilizer system what state (open/locked) the cylinder is in.

 

[Brutherb]

Same here and known issue with lock actuator motors when they are on their way out. There is a large "Door Lock Actuator" thread that will tell you what you need to do and which model motor you should buy for your year vehicle.

As for the lock itself being powered, no. There is a motor assembly that drives the lock cylinder via cables. Then there is a ring sensor around the lock cylinder that tells the immobilizer system what state (open/locked) the cylinder is in.

Could you post a link to the door actuator thread that your talking about as I am sure if I search as I have several will come up.

 

[gregnash]

Could you post a link to the door actuator thread that your talking about as I am sure if I search as I have several will come up.

This one...

Door Lock Actuator Replacement

I had the normal symptoms of a door lock actuator gone bad (many threads on this) so I went about investigating this issue over the weekend. I was hoping I could find something that could be remedied by a little bit of cleaning / maintenance, but that wasn't the case. Removal of the door...

forum.ih8mud.com

 

[Brutherb]

Thanks, if the rear hatch lock cylinder does Not lock or unlock any of the doors, but the actuator works if I use the electric locks switch on the door, is that a wiring issue then,

 

[gregnash]

Thanks, if the rear hatch lock cylinder does Not lock or unlock any of the doors, but the actuator works if I use the electric locks switch on the door, is that a wiring issue then,

Likely could be as there is a lock sensor that is attached to that lock cylinder as well. I would start with a good cleaning of the cylinder and clean the sensor (backside of cylinder) with some electrical contact cleaner. Make sure that it did not get unplugged at some point in the past, etc.