Hi All,

I currently have a Mazda6 2008 Sport diesel 2 litre which is showing some weird issue. I noticed a few moths back my dashboard lights and interior lights were slightly flickering. Then when i start my aircon in the car i notice my voltage drops from 14v to 11v and then the battery light comes on. I had called RAC and had informed me that it is the alternator and not the battery. However i have had both alternator and battery replaced but no changes in behavior. Can anyone here on this forum advise what else i can look at as i am puzzled to what it can be?

Thanks,

Anowar

 

Check the battery ground cable for corrosion where attach to chassis. Create a heavy electric load turning AC, lights etc and with a Voltmeter measure from battery post to a clean chassis point or engine block and if you measure any significant DC voltage you have a bad ground. A thermal camera is also a good troubleshooting tool because a bad battery ground point would generate a good deal of heat.

 

The Alternator is controlled by the ECU/PCM. I have seen ECU/PCM's fail in the past and cause charging issues.

 

Thanks for your advise. I will check the ground lead and see if there is any corrisions.

 

Is there anyway i can check if the ECU is the problem. I have an odb reader for the car but not sure if this will detect it. Also after the alternator was changed is there anything that i need to reset on the car?

 

The reader will only show DTC and maybe readiness monitors? To test ECU charging rate and other values related to the alternator output control you need a professional type scanner diagnostic device like a snap-on Solus.

 

You are simply the best!!! It was the ground cable connected to the chassis. I unscrewed the nut first and then screwed it back on and now I don't see any flickering or loss in power with intermittent battery light coming on when everything is on. Thanks a lot for that mate.