Speedometer & electrical gremlins - 2001 Boxster 2.7

[utkayaker]

I have been working through issues from my '01 Boxster "barn find", but need some help

What speed sensor(s) "drive" the analog speedometer? (By the way, the digital one and the odometer doesn't work either.)

I pulled the left rear speed sensor and I tested it with an ohmeter and it register 1.7 so it seems to be within spec.

Can I clean the speed sensor?

I did check all the fuses with a little fuse tester.

Also, the ABS light is on, the check engine light is on and the spoiler is stuck in the "up" position

Other problems I still have (so you can tell me how to fix them or if they are related)
Power window switches don't work (but the windows will roll themselves down and up when I raise and lower the top)
Radio doesn't work. (The battery died after sitting dormant for 9 months.) I think I just need to get the code from Porsche
Cruise control stalk is broken and hanging by wires from the steering column - could this have an impact on the speed sensors?
Right rear running light is out but I haven't checked the bulb yet.

Any ideas are welcome!!!