Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Most likely the problem will either be internal in the powertrain control module, its programming, or the wiring leading to it, bad grounds etc, possibly a faulty wiring harness, this issue will require inspection of all wiring for rodent damage, a live data scanner with the capability to reflash programming of the powertrain control module, and very accurate color coded wiring diagrams and component location index. The loss of power and the electrical could possibly be separate issues as well. If you do not have the specialized equipment and knowledge to use them you are likely to spend more than you need to ,to solve the problem. Please rate my service, if you have additional questions i will answer them until you are completely satisfied with my answers.
Powertrain control module is the engine control module in the left front corner of the engine compartment but you have to understand that it is the central interface for all other modules on the vehicle ,this problem may be specific to your vehicle only and info will not be on forums, only Master Certified Techs with 30 + years have come across these type problems. Professionals rarely use a forum unless it is a widespread problem across the country that is publicized by the manufacturer utilizing technical service bulletins available to dealerships.