2006 Sonata headlights dim while driving

My 2006 Sonata's headlights will dim on low beam for a second or two,
then return to their normal brightness. This happens while driving at
night (duh! it's more noticable), I tend to notice it the most when
the car is downshifting from 2nd to 1st. Any ideas?

 

Alternator perhaps

 

Mine does the same thing. I had not paid attention to what gear(s) it
appeared to happen in, I had only noticed that when I slowed to make a turn
such as off the road into my driveway, it would occur. I have not
investigated this at all, but I do see it in my 06.

 

Yes, but it does not necessarily mean it is a problem. My Sonata MY2002 made
the same and there was a TSB describing this as "normal" behaviour of
alternator regulation circuits.
Anway, you could verify if battery connectors are tight.

 

Nope - not a battery connection problem. Not even symptomatic of one. I've
chocked it up to just a nuance of the car.

 

I recently worked on an Azera that did this. Verified that system voltag
basically dropped to battery voltage (no alternator contribution) whe
this occurred. Seemed to occur off gas, but not necessarily at lo
speeds. Put an alternator on; owner reports no change.

Hyundai recommends checking battery cable voltage drops, junction bloc
connections, and ground lugs. Customer has yet to return for furthe
checking

 

Have the same problem dealer could notified fix?

 

OMG there are many member who have the same problem.. Have anyone replaced the head light unit ! because it may be due to the poor head light. But as you are saying its new then it don't should do this. Anyhow I am trying to find some solution for that. guys just stay here I will reply the solution soon.