Dim low beams
 

Hi all. New to the forum. I bought a 2011 Elantra Touring new and it currently has a little over 80K miles on it. The reason why I'm here is that my wife just got home from the store and told me the headlights were barely working. I went out to check and sure enough, the low beams barely light up the door of the garage. The high beams and all other lights seem to be working fine. I would think that if the bulbs had an issue they would burn out entirely, also why would both have the same problem. Seems like an electrical issue to both headlights. Anyone here ever experience anything like this?

Low beams full glow. Same problem.
 

Does anybody know how to fix this problem

Can't tell how to fix the problem until we know what is causing it and where..

Since power comes from the headlight switch goes thru the dimmer switch then down to both low beam wires at the headlamps, the poor connection could be anywhere in between.

No, that's not correct. Power for low and high beams are supplied by separate relays located in the "engine room junction box" (left side), as indicated by the Head Lamps schematic diagram. Since both lamps use the same ground and the high beam bulbs appear to be the proper intensity, it's unlikely to be related to a bad ground connection on both sides.

I would try swapping the low & high beam headlamp relays first to see if this is caused by a faulty relay:
https://cimg1.ibsrv.net/gimg/www.hyu...611051c35a.png
Part number for this relay is 95224-2D000 (up to 6 of these installed, depending on equipment). --g

Thank you for explaining the set up.
The only way the relay could defective would be if the contacts to the headlamps was corroded. Because the lamps are functioning, but are apparently getting insufficient power to operate at full power we know the relay is working. What we need to do is see where the poor connection is between the relay and the low beam lamps. That power must go through the dimmer switch.
Can you supply a wiring diagram so the path can be seen and followed to decide where we would look for the voltage drop, thanks.

Power to the headlight lamps is supplied by separate low & high beam relays, and, in the case of low beams, separate left & right 10A fuses in the ERJB:

https://cimg3.ibsrv.net/gimg/www.hyu...c16ebb1f0c.png

The steering column multi-function switches (lights, high beam/flash) send signals to the body control module (BCM) terminals 6 & 22. BCM terminal 33 output triggers the low beam relay (and powers the high beam/flash switch), which supplies 12V to both left and right low beam lamps; this is where voltage drop could occur. When the high beam/flash is engaged, signal power is sent to BCM terminal 22 and the high beam relay trigger. Thus, the multi-function switches do not supply power to either low or high beam lamps directly. --g

Thanks for the diagram.
What we need to verify is,
Are we getting 12 volts at pin 17 of the junction box.? What we get there will determine where we go .
We could also start at any low beam headlamp and see what voltage we are getting there .
There should be a voltage drop from the headlamp as compared to pin 17. How would you suggest we check for the loss of power to the lamps.?

Rule out a faulty/failing low beam relay first -- that's easy. If the relay checks out OK, continue by measuring supply voltage at various points: terminal 3 of the the headlight connector, the 10A low beam fuses in the ERJB, and the relay terminals. --g

Now we get to the good stuff.
Do either John or pk have or have access to a multimeter and have some idea how to use it?
There is no sense printing out a whole list of instructions only to have the person take the vehicle to a shop because they can't do the checks.

Alas, typical behavior from many people on these automotive forums (I follow several in the Volkswagen-Audi world, too): join to post a question about a fixing a problem, then rarely follow-up with a diagnosis or a solution for their original "problem". Poor forum etiquette, IMO. Maybe @Johnpars will show up here again and offer some follow-up on this; it's only been a few days since the original post... --g

A lot of folks just want to have some idea how to explain ?? or seem to know what to have a shop check.
That is why many times I will ask are you going to do the work yourself or take it to a shop,,,,to hopefully reduce time and effort attempting to explain a procedure.
That is why I will suggest up to a pint and hope to hear what results they receive before wasting a lot of time with a series of steps and explanations that will not be used.

They are on just about every forum and that is just the way it is.

I'll add that I'm on this forum because my sister a couple states away has one of these; it's a nice enough car -- drives well and gets decent fuel economy, though it's not the trim that has the roof carrier rails (too bad). When she has a problem with it (rarely, so far), I get to do some research to save her a trip to either the local dealer or indy import shop, order up the parts, and have a go at it on my next visit. The kind of problem described here could happen to her 2010 Touring, so I don't mind taking a little time to look at possible root causes, which could be useful info (or not) in the future. --g

I would be reasonably sure of you having experience in the repair field , are aware of the value of regular maintenance.
However, a lot of folks believe regular maintenance consists of just oil and filter changes. So we try to expand some of their knowledge by constantly reminding them there is more to regular maintenance than oil and filter changes,,especially when done by discount quick oil change service places.
You are probably aware that that book in the glove box is there for something to read while waiting for road service.or a tow truck. So if it is of any value , I try to suggest that they go by the maintenance recommendations in that manual. There is a wealth of info in there.
The last thing to do is to take your vehicle with a problem to a shop/dealership and proceed to tell them how to fix it.
If they do as the customer directs and that doesn't correct the problem ,they blame the shop.
I have seen quite a few times when info put forth on some forums is not reliable.
Anyway, glad to have another experienced person join and help the folks that really need it, thanks.