Speed Sensor Wiring

I just had my speed sensor replaced (3.4L 70000k miles) and the lights are on again, i have read a lot about the wiring issues. Where can i look to see if the wiring is bad and where can i find the wires and how complicated are they to replace

Are you referring to the wheel speed sensors? Assuming you are the wiring runs from each sensor electrical connector found at each hub to the ABS modulator located on the driver's side front end. It is bolted to the subframe assembly. To access it you must remove the plastic splash guards. From there it goes to the EBTCM (electronic brake and traction control module) module which is located under the dash. To check wiring electrically you'll need the Alero wiring diagram from the FSM and a DMM. Otherwise all you will be able to perform is a visual inspection of the complete wiring.

if the wiring does end up being bad where can i find the replacements

You should be able to get the wiring harnesses and electrical connectors from a GM dealer. Your other option would be a salvage yard. However, for example if you find one or two wires damaged/cut on the wiring harness at the hub/sensor or along the control arm you can repair it by splicing the wiring and using heat shrink to protect the connection point.