When driving my 2000, the power door locks open and close on their own. In a 15 minute drive, the locks will activate 3 to 4 times. I have the factory remote system with a Viper alarm that uses a transmitter to open/close the doors and arm and disarm the alarm. Once the car is parked and the alarm is set, there is no problem. Is there a power door relay that I can check or replace? Thanks in advance. Jerry
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Power door lock problem
- Thread starter Jerry@Mobile
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There is no power door 'relay'. There is a power door lock control unit; however, I expect that its replacement is probably expensive enough that you do not want to go replacing it on spec. The service manual takes you through a rather detailed process for confirming that the unit is operational or faulty.
The door locks closing and opening on their own would be unusual. If you were driving the car and they locked on their own, you opened them and then they relocked, you opened ..... or the opposite where you locked the doors and they repeatedly unlocked themselves, those two scenarios would be easier to understand. If you look at the schematic for the power locks in the service manual, you will see that a lock or unlock operation is initiated by applying a ground to the appropriate input on the power door lock control unit. That is what the switches on the inside of the door panels and the switches on the lock cylinders do. So, if you have a faulty connection that could be applying a momentary ground, that could be causing the locks to open or to close. I suppose that if a contact in one of the door switches was flopping around internal to the switch, that might be causing the locks to open and close on their own if you were driving on bumpy roads. Not impossible; but, it does seem a bit of a stretch to me.
The power door lock control unit gets a signal from the ignition switch that there is a key in the switch. The service manual implies that if the control unit is not getting this key in signal the doors will relock. If this key in contact is intermittent it might be causing your problem. When doing the control unit function test you could wiggle the key in the column lock to see if the contact has become intermittent.
However, before you do any diagnosing on you power door locks, I would isolate the viper alarm system from the factory wiring and do a drive around test to see if the door locking - unlocking persists with the alarm disconnected. I know you say that when the car is parked and the alarm is set there is no problem; however, I have had two aftermarket security systems that started doing screwy random things after a couple of years of operation. Best to rule out the aftermarket stuff as the source of the problem which should be easy to do.
The door locks closing and opening on their own would be unusual. If you were driving the car and they locked on their own, you opened them and then they relocked, you opened ..... or the opposite where you locked the doors and they repeatedly unlocked themselves, those two scenarios would be easier to understand. If you look at the schematic for the power locks in the service manual, you will see that a lock or unlock operation is initiated by applying a ground to the appropriate input on the power door lock control unit. That is what the switches on the inside of the door panels and the switches on the lock cylinders do. So, if you have a faulty connection that could be applying a momentary ground, that could be causing the locks to open or to close. I suppose that if a contact in one of the door switches was flopping around internal to the switch, that might be causing the locks to open and close on their own if you were driving on bumpy roads. Not impossible; but, it does seem a bit of a stretch to me.
The power door lock control unit gets a signal from the ignition switch that there is a key in the switch. The service manual implies that if the control unit is not getting this key in signal the doors will relock. If this key in contact is intermittent it might be causing your problem. When doing the control unit function test you could wiggle the key in the column lock to see if the contact has become intermittent.
However, before you do any diagnosing on you power door locks, I would isolate the viper alarm system from the factory wiring and do a drive around test to see if the door locking - unlocking persists with the alarm disconnected. I know you say that when the car is parked and the alarm is set there is no problem; however, I have had two aftermarket security systems that started doing screwy random things after a couple of years of operation. Best to rule out the aftermarket stuff as the source of the problem which should be easy to do.
Thank you for the reply. Since I posted the query, my alternator went south. I had it rebuilt and the internal voltage regulator, rectifier as were a few of the diodes were replaced. I noticed the voltage gauge was dropping ever so slightly. Upon reinstall, the door lock problem did not occur on my way into work today. I will keep an eye on the situation and report back in a few days. Again, thanks for your help. Jerry
Update. I traced the problem to the power door lock control module. The list for it is about $400. I ended up purchasing one used for $87 delivered to my door. The install took all but 10 minutes. Problem solved. Hope this helps someone in the future. Jerry
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