My 99 Accord EX Sedan has been having issues with the power lock system. It started with just the passenger side door where the lock would sometimes work and then sometimes not. It has progressed to the point where I now have to manually open it everytime I let my passenger in.

The two rear door locks have started acting up recently as well. Right now they will variably work (I would say they dysfunction 1 out of every 5 times I unlock the car). Their non-operation is not dependent on each other because sometimes the rear drivers side will dysfunction and not unlock (or lock... it happens in both cases) while the rear passenger side will unlock and vice versa.

This is an issue that is present with both the keyless entry remote and the hardwired door lock switch.

I have had no issues with the driver's door power lock.

I am looking for advice on where to start looking for the problem. Please let me know if any further information is necessary to address this problem. Thank you in advance for your assistance.