Volkswagen: 2002 Golf GTI Electrical Problems, obd ii scanner, switch spring

Question
Hi, the "check engine" light on my '02 GTI (California) 1.8T automatic is constantly lit. In addition:

The driver's electric window does not currently glide continuously up and down at a single press of the power switch - it stops moving when you take your finger off the switch (the spring in the switch also appears to have gone more recently). The "alarm off" button of the key remote does not work and, every time I turn the key in the ignition, the alarm goes off until I actually turn over the engine.

Are all these issues rooted to the same electrical fault, other than perhaps the switch spring? I've heard VWs are notorious for developing electrical problems. I don't want to take the car to a VW dealer as they have scammed me before on labor diagnosis costs without actually doing any work (I reported them to AAA). No other mechanic seems to have the right diagnostic tool to get to the root of it.

Answer
Jason,
 The check engine light is a very general indication of literally thousands of possible error codes detected by the computer.  The bad news is you need another diagnostic scan to find out what it is.  The good news is anyone with $100 can buy an OBD-II scanner on eBay and do it yourself.  Now $100 seems like a wash when you can just pay the dealer that much or less for the service, but here's the kicker.  If you get your own OBD-II scanner, you will save everytime you get a check engine light in the future (and you WILL).  Also is will work on almost ANY car (be a hero to your friends and family.)  You can look up any code you find at www.obd-codes.com.  You can also reset the check engine light.  Now a scanner won't fix the problem, but you may get a clue to DIY, or at the very least the shop won't be able to BS you as easily about the true problems.