Q: Security light constantly on or flashing, battery light flashes, radio locked, power locks and dome lights don't work. Please help

Hi there, thanks for writing in. I’d be happy to provide my insight.

I would not replace the BCM without a thorough diagnosis first. GM vehicles such as yours suffer from two small wires that break in the steering column. They attach to the ignition lock cylinder that is part of the security system. But this doesn’t cause all the other power problems and the car will crank every time. If the security system is acting up, you can turn the ignition in the run position for ten minutes. If the car starts after ten minutes, then you most likely have a security issue.

The first thing I would do is to connect a scanner and see if I could communicate with all the computer modules. This will be a good indicator of whether or not the BCM is failing. In addition, any codes that are stored could be retrieved and these are very often excellent guides as to what is the problem.

If I were working on your car, I would look at all the connections that supply power to the fuses. This will require a repair manual or access to a professional level automotive information system. Following this, I would study a wiring diagram to see if there is a common connection that supplies power to all of the systems that are not working.

When it comes to computer modules, they are rare to fail. For this reason, I rule out every other possibility first before I suspect and then begin to directly test the suspected module. I recommend the following inspection to help you diagnose your car: Electrical problems are not working inspection.

Hope this helps, and best of luck.

Good luck!