How do I diagnose low beam headlights not working? High beams are OK

Dennis, Make sure the low beam bulbs are OK, first. if fuses and grounds OK, it will be your multi switch, which you nay be able to disassemble and clean contacts.
Low Beams Not Working Resolved

How to Fix Low Beam Headlight

Low beams out high beams work

Acura TL Headlight Replacement WITHOUT removing the bumper

bad connection or bad earth check all connection or bulb

I would check for the groundwire continuity

Driver side - dim low beams and no hi beam - Subaru Outback ...

www.subaruoutback.org > ... > General > Electrical & Electronics

Oct 11, 2014 - Hi everyone, My drivers side headlights are dim on low, (car has separate bulbs ... When the headlight switch is turned ON, but for low beams, ...

Driver-side Low beam Not Working (electrical issue not bulb ...

www.hummer4x4offroad.com/.../showthread.php?...Driver-side-Low-be...

Mar 12, 2015 - 10 posts - ‎4 authors
The high beam continues to work on both sides...I pulled the Driverside headlamp fuse and then both left and right beams lit up but very dim.

High beams ok, but not low beam - one side only - TDIClub Forums

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Jan 23, 2014 - My driver's side lights are working fine - high and low beams. ... But it definitely looks like the big lamp on the driver's side gets brighter when ..... Drivers side headlight is very dim on low beam and goes out when on high beam ...

Dim driver's side headlight (low & high beam) - GrandAmGT.com Forum

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Dec 11, 2002 - 6 posts - ‎4 authors

First check light relay fuse, if ok check battery voltage at low beam light terminal, if ok replace low beam bulb, if no voltage check switch side of relay, if voltage replace relay, if no voltage check headlight low beam switch.

It is very common for both headlights to be bad, as we use our low beams a lot more than high beams. I would first suggest replacing the headlight bulb. The low beam filaments could be bad and the high beams be ok. If this doesn't help feel free to let me know and I will be happy to look a little deeper for you.

Moe likely a bad earth for one of the lights as one light is working through another causing one to stop working

If your highbeams are working fine, you must be referring to your low beams not working I would simply check the 2 bulbs and make sure the low beam filament is good, theres a strong possibility that your BOTH low beam filaments are bad and require replacement of both headlight bulbs to get them working again its a very simple repair.....

It could be in the switch for the low and high beam's

You need to start by checking the fuse for your headlights (low beams). The DRL could be be bad, but I have not seen them go out very often.

Clyde,

I've been troubleshooting this same problem on a different vehicle this week, and I can give you the steps I'd take.

1. If both sides went out at the same time, the problem is *NOT* likely to be the bulbs.

2. Check the fuses to see if both low beam lights are on the same fuse. Many cars have one fuse for low beam and another for high beam, so both lights out at the same time typically means fuse blown.

3. If the headlights are OK and the fuses are OK, then the problem is *LIKELY* the headlight switch. In my case, AutoZone has one and it can be installed easily; but in your case, that may not be as simple.

Please post your findings or comments.