My rear passenger side window won't work. How do I tell if it's a regulator or some other problem, like a motor, before I go ordering parts?

 

when you press the button do you hear any noise? If not pull the window ecu and resolder the joints. Report back

 

The window ECU is located behind the glove box. You can remove the connectors and pull the PCB out of the housing instead of trying to unbolt the housing.

Usually a cracked solder joint.

 

Okay, there looks to be one (ECU) up in behind the glovebox that I probably need to pull the glovebox to get at, and one below it, against the kick panel. When I pulled the connectors off the lower one, the working windows still work, so I'm going in for the other one later. What is the lower one?

 

...forgot to add, that's probably the problem, as there is no sound at all when I press the switch for that window.

 

You are going to have to remove the glove box, to gain access to the ECU. Dang, I had pics when I resoldered mine but I can't find it. Let me keep looking.