Power window switch?

[catdaddybaycali]

Bit of a puzzler, this. I have a 2000 Honda Civic LX 4D. My passenger side front power window sometimes works and sometimes doesn't, whether you use the master switch on the driver's side or the switch on the passenger side. The dealer wants $130 to run an electrical system diagnostic. I'm thinking it's probably the passenger side switch, but I know nearly nothing about electrical systems. I found a front passenger side switch on ebay for $30. Do you think it's worth buying and trying the switch, or should I pay for the diagnostic? Any input would be greatly appreciated. Thanks.

 

[mc360]

Can almost guarantee that it is not the switch, the most common problem are the wires that come into the door plug, they pull out of the pigtail from the door opening and closing all the time. The driver door affects both sides.