silvercivic01gr

My 2001 civic coupe does not come with keyless entry. A couple of years ago, the central locking quit working. It used to be that locking/unlocking the driver door would lock/unlock the passenger door but not anymore. I have to use my key to lock/unlock each door individually or use door switch (button) when I'm in the car to lock/unlock the other door. Every time I lock/unlock the driver door, I would hear two clicks. One click seems to be from the acuator (driver side) and the other click seems to be from the unit underneath the steering wheel. All fuses and other components (e.g. power window) are fine. Is there a way to diagnose the problem without removing the door panel? I don't think I can remove the door panel by myself and may end up taking my car to a mechanic or sell my car as it is.

silvercivic01gr

Since I can hear the clicking from the MCU/fuse box, does it mean the signal is sent from the driver door to the MCU but it doesn't get to the passenger door? That's what I hope, so I don't have to remove the door panel. I was trying to look for a diagram but couldn't find one to explain the wire from the driver door to the passenger door.