Last night I completed the installation (or so I thought) of the HU in my 1990 W124, and followed many of the directions from the DIY section here. Rewired all speakers, prewired for amp and sub, but when I reconnected the battery, saw small spark, didn't think much of it, but now power windows, sunroof and rear defrost no longer work. All other electrically things are working, checked fuses and they seem all okay. Any suggestions on where to look?
I used the crutchfield wiring harness, so felt that connection went smoothly. But the radio isn't working either, although it has power(enough to eject shipping material in disk area).

Okay after much reading, I'm hoping it's the convinence module under the rear seat that may just have a loose connection. As it may have been knocked after taking the rear seats out twice in the last two days for rewiring all the speakers. Fingers crossed.

This seems to make the most sense since they stopped working at the same time. If it's more than just a loose connection, any idea what a replacement would cost?