1999 VW Jetta Wolfsburg experiencing numerous electrical problems

1999 VW Jetta Wolfsburg mileage: 84,000. I have been experiencing numerous electrical problems over the last two months. The rear power windows only work sporadically and when they decide not to work there is no noise they just don't go down. A couple of times each week my coolant indicator light comes on for a while then goes off. My coolant level has not been low. There is no change in the temperature gauge and no smoke/leaks/etc that would indicate any problem w/the coolant level. My alarm activates itself on occasion when I am driving. I know this because I'll be driving and I see the red light on the driver side door lock start blinking as if the alarm is set, also the horn beeps just as it does when you lock the doors from the outside and activate the alarm. Furthermore, when this happens I cannot unlock the power locks unless I use my keyless entry key chain (which doesn't work outside the car) inside the car. That is the only way I can de-activate the alarm and unlock the doors. I have had my vehicle into two VW dealerships, paid for diagnostics and they tell me nothing is wrong and that the car is running to manufacture specifications. I have been corresponding with VW customer relations as well. So far, no answers. Any suggestions?