2008 Santa Fe w/2.7L and automatic trans.

When slowing down, the headlights dim briefly. This appears to be only happening when the transmission downshifts but is extremely noticeable from 2nd to 1st shift. The rear lights and the interior do not dim; only the headlights. I have noticed a quick dip on the tach when this happens. Dealer says could be battery but tested as good.

Any ideas? This is becoming a little annoying as I drive in stop and go traffic usually in the dark.

 

Sounds like you have a lot of load on the system like headlights, heater fan, wipers, etc all going at the same time. Battery might need a charge, but it's not an "abnormal" thing in winter at night.

 

http://www.hmaservice.com/files/331/5002040/08-BE-004PDF.pdf

 

Thanks jsinton for the info. My father had a charger and we hooked it up but the charger showed fully charged so no good there.

 

That link provided what I was looking for. It describes it exactly so I will bring this in to the dealer and have them work it. Thanks, I will look over that site later for more good information.

You've both been very helpful.