I had recently bought a Mazda CX-9 (2008 model) and spend the last two days hadrwiring a Viofo dash cam using the HK3 kit. All worked fine but before I wrapped up, I tried starting the car but to my surprise, unsuccessfully. There is audible clicking sound but that's it. I suspect that it might be just a drained battery. I've unplugged all fuse taps (those were connected to SUNROOF and OUTLET RR) as well as a negative lead I bolted to chassis but still no luck. While installing the dash cam and doing other things around the car, I had door open and the cabin light was on for quite a while. I really hope it is just the drained battery. Is anyone able to confirm this? Cheers.

Here is a video:
https://www.dropbox.com/s/rfzv14cj6g...rting.mp4?dl=0

 

I don't have a proposed solution but just an observation. From watching the video, it seems the engine is actually turning the same way it would when trying to start it - but not firing. The sound in the video seems more than just clicks. Leaving small lights on while you worked won't easily drain a battery so I somewhat doubt that's the problem.

 

The simplest voltmeter is only a few dollars and has more than sufficient accuracy to determine battery voltage as well as other simple trouble shooting.

 

Thanks guys, got a voltmeter as PTguy suggested, it read 9.64V (lol). A new battery solved the problem.

 

A lead-acid battery is 100% charged at 12.7 volts, 50% at 12.06 volts, 10% at 11.31 volts, and 0% at 10.5 volts. If yours dropped to 9.6 that easily, it was ready for replacement.