Light goes dim

I have noticed when I accelerate my lights dim for about 2 seconds. It's quick but noticeable. I have a 2014 Limited. Anyone know what may be causing this? Thanks.

 

possible loose fan belt, possible weak alternator, So first thing I would check is the belt tension make sure it is not too loose or the belt is worn.

Then If you have a Volt meter check at the battery what the voltage is without the engine running should see 12.6 VDC or very near that, Then start engine check again and see what the voltage is should fall some where around 13.4 to 14.4. if you are not seeing an increase in the voltage with it running the Alternator may be on its way out but have it checked at one of the local auto parts stores because many of them do have setups on hand to check batteries and Alternators Just hope whoever is behind the counter knows how to use it.