I have a 2010 Lexus ES 350 that I just bought from a coworker. My coworker has owned it for many years and basically had no trouble out of it besides needing to replace the radiator. Except for one nagging problem, the door locks.

The Problem:
The door locks on the vehicle intermittently work, they definitely work less often than they don’t. It is not an actuator problem as all four door locks operate strong when the system is working. I tried to do a fair amount of wire tracing and I cannot seem to find the problem.

The locks will start working and stop working at random times, sometimes halfway through a drive I can reach over and hit the switch and they will work,10 minutes later the switch will do nothing. The switches on the other three door doors do the same thing, so I do not believe it is a switch problem.

I’m starting to think it is a problem with the body control module, but I don’t seem to have any other issues. I would think if the module was starting to go out that other issues would appear. I found a wiring diagram online, but I have trouble deciphering some of the connector locations and the pin out of them.

I’m open to any and all help here, it is a real pain to have to manually lock all four doors every time you get out of the car. Unlock functions work totally fine.

I do not have access to any type of scan tool, but if I did, would that tell me if the body control module is seeing the input from the switch? It seems like if I take something to the dealer it’s going to cost me $500 just to have it looked at. I’m kind of a DIY guy so I would love to get this fixed on my own.

 

Have you looked for a local independent Toyota specialist shop? Most of this vehicle is identical to a Toyota Camry. So a Toyota dealer could also check it out, many members use Toyota dealers for maintenance and repairs.
This database may help you find some well regarded repair shops in your area, once you find some, cross check them on Google or Yelp as some of the reviews can be old. It lets you search by city and state and even car manufacturer.
https://www.cartalk.com/mechanics-files

 

Shameless Bump…

I have not talked to a local Toyota expert. Maybe I need to look harder, I know a Honda specialty shop, but not a Toyota one. The previous owner had it looked at by the Lexus dealer recently. They had no answer, but sometimes I feel like dealers put very little effort into diagnosing older cars.

 

Just a guess but the issue could be related to the master door/window switch on the driver's door. You might want to try unplugging and replugging in all of the connectors to that switch.

If that switch has issues it will affect all doors.