Power Door Locks Not Working – Diagnose and RepairJuly 4, 2009 10:02 am Automotive Consumer, DIY
Wiring can cause door lock problems, switches and actuators are more common
There are several things that can cause the power door locks not to work properly. The most common cause of a single door lock not to work, is a bad door lock actuator (also called a door lock solenoid). Another common problem or cause of door locks not working is simply a bad door lock switch. Many cars today have computers that are also in the loop when it comes to controlling the door locks.
Fortunately, body computer systems are pretty dependable and give problems seldomly. It seems as though the most troublesome vehicles regarding door locks related to computer control issues, are Chrysler’s; Dodge Caravan and Chrysler Town & Country vans sometimes have BUS related issues (BUS means “a collection of wires through which data is transmitted from one computer to another”)… but this is still rare. Ford Explorers also have a few BUS issues that can be related to door lock security module, or wiring shorting out that goes from the door into the body. Usually when checked with a scan tool in the body control or security section, there will be a code indicating if there’s a BUS fault.
Problems can also include other failed parts that aren’t high tech, like a linking rod connector. Sometimes the linkage can pop off during the process of a locksmith using a slim jim or someone using a hanger to unlock a door. It’s easy to hook onto a rod and disconnect a link. In this case it’s just a matter of removing the door panel and maybe adjusting the linkage and replacing the plastic rod retainer if it was weakened or broken.
Door latches can wear, some have the door lock actuators built in and others don’t, but a worn latch in either case can cause problems. If there is too much play or excess movement, the door lock may not work dependably. When replacing door lock actuators, a lot of times they are only available as an assembly including both the door latch and actuator as a unit. It depends on the make and model how they are which design they have.
Door Lock Diagnostics. First think about the problem logically.
1. If there is only ONE door lock not working, the problem is more than likely isolated within that particular door, barring some unusual wiring issue.
2. If all the door locks work with the passenger side door lock switch, but not the driver’s door lock switch then the problem is more than likely the driver’s switch.
3. If a single door lock only works in one direction, either to lock or unlock but not both, then the problem is likely to be the door lock actuator.
4. If ALL door locks work only in one direction, ether to lock or unlock but not both, then the problem is likely to be a bad door lock switch.
For more questions and answers see the second part of this post.
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