My headlights and cabin lights have suddenly started to flicker at idle. I've had both the battery and alternated tested and both came back normal. Not sure what the problem is, any insight?

No other issues such as crank, power, etc.

2006 2.2L

 

Maybe a loose connection, fusebox halves, or ground.

 

I'd throw a voltmeter across the power connection on the dash below the heater controls, to monitor the voltage while stationary and mobile.

 

failing alternator, low idle.

 

Yes. Alternator is probably on its way out. Mine did the same thing for a year before the alternator revealed itself as the culprit. I was gonna say something but wanted one of the all knowing gurus to confirm my assumption before leading you astray lol. If you replace the alternator give it a Happy New battery to charge too!!

 

He said the battery and alternator both tested good.

 

Loose grounds

 

Maybe I'm just too old, but I can't think of a scenario that the charging system could check out good when the lights are flickering at idle.

The idle is too low for the alternator the provide sufficient juice. That could be that the alternator is not functioning properly at a normal idle or that the idle is lower than it should be, for some reason. There is a tachometer right on the dashboard, it should be steady.

The description that it is always flickering at idle and always clears up a speed means that it is not intermittent.

 

Here's a video of it

Also it's does not go away with speed I was wrong


Also test receipt photos:

 

Battery voltage is low (12.2) - and CCA is low as well. with the voltage dropping below 10V on starting (it actually dropped below 9V according to the graph), I'd replace the battery.