I'm trying to help a nurse that my wife works with. She's got a 2019 Charger SXT AWD+ with Bi-function HID headlights. She was stopped yesterday for having no tail lights. I went to look at the car today, the LED Halo (for lack of a better descriptor) tail light works when the headlight switch is in the "parking" or "headlight" position, but not when it's in the "Auto" position. If the tail lights work in one position of the switch but not another, I'm assuming it got a problem with the switch. I called a buddy that works in the parts department at a Dodge dealership, but he said that they don't sell a lot of headlight switches for late model Chargers.

Anyone have any experience with this type of issue? Any other tests that I can do to conform a bad switch before I suggest that she buys a new switch (which I'll replace for her)? I've searched "Head light switch" and "no tail lights" in the Charger section of the forum without much luck. I've also scanned the first 24 pages of threads that goes back to 2019 looking for any "lights" threads to no avail.

I'm trying to keep the cost low for this friend of my wife. Thanks for any assistance...

 

I don't think the switch actually directly controls anything. I believe it simply suggests to a computer somewhere that it should turn the lights on.... or, it leaves that decision up to the computer, and the computer has a light level sensor somewhere..... Best way to figger that one out would be havin' a look at the wiring diagrams, but, considering how new it is..... They aren't readily available online yet. You *might* be able to pick up a digital copy of the Factory Service manual for a reasonable price...... Chiltons or Haynes won't be detailed enough.

 

If she was stopped for no taillights, that officer may have meant no brake lights, unless it was dark out and the lights should have been on. Have you checked the brake lights for proper operation?

When in Auto, the taillights will only illuminate if it's dark enough or maybe if the the Daytime Running Lights are enabled. There are some manufacturers that for some reason don't turn on the taillights with the DRLs, but I don't think Chrysler is one of them.

-Rod

 

I did check the brake lights and they appear to work properly. I'm going to have her bring the car by after work and allow me to test it more completely now that I know more about the "proper operation" of the lights which includes a "light sensor".

I anticipated the same idea that the switch doesn't control much other than the signal to the computer to set it in one of the three operation modes. But I do find it odd that the "taillights" (the LED light that surrounds the rear of the vehicle) worked properly in both "parking" and "lights" mode, but not when in "Auto".

I hope to have more info this afternoon.

I appreciate the assistance.

 

When you checked the lights in the Auto setting though, was it dark enough that the headlights came on? Do you know that when she was driving the car she had the switch in Auto? Were the headlights on, or were they maybe just Daytime Running Lights (DRLs) that made her think headlights were on?

-Rod

 

I had her bring the car by the house yesterday, so I could check a few more things. This is getting more complex. Now the headlights NEVER come on; no matter setting the switch is in. I used a dark towel to cover the "light sensor" on the dash. There is a quick "double flash" in the left (driver's side) headlamp when I turn the switch to the "headlight" position (two clicks to the right from OFF). I got the taillights to work in AUTO by turning it on after I started the car, but still no headlights.

So, taillights and brakes appear to be working properly. NO headlights: no matter which position the switch is in, and a quick "double flicker" of the driver's side headlamp when turned to the "headlight" position. All with a towel over the light sensor. No difference with the towel off the sensor.

It's got me wondering if the light sensor is bad.

Are these a "known" issue with the late model Chargers? Could it just be time for new headlamp bulbs? What's the life expectancy of the modern HID bulbs? I don't just want to throw parts at it, but I'm not sure what other diagnostics to do at the moment.

I do own an Autel MaxiSys Elite that I inherited after a friend succumbed to Covid a couple years back. I can navigate through the basics but am not sure if there is a way to use it to do more extensive diagnostics of the automatic headlight system.

Again, any assistance is greatly appreciated.

-- Cornelius

 

I've been doing more research about the HID system in these cars. What ever happened to good ol' halogen headlight bulbs?? The D3S bulbs in this car are about $280 each and they require an igniter (igniter attached, but still more complexity leads to greater expense) and a ballast. How do average folks afford changing the bulbs in their headlamps when they go out?

Now I'm wondering about the ballast. In one video I watched, they noted that the flicker indicates that the bulb might be good but the ballast may be going. This makes some sense as the owner stated that last week it seemed like her headlamps we "dimmer than usual". The video mentioned that this is also a sign that the ballast might be going out. Of course, I don't know the person that made the video and they could be just as clueless as I am about this complex system.

As always, thanks in advance for any assistance that you can offer.

 

The flicker could also be due to the ignitor failing. The ballasts are not pleasant to replace. If it's like my 2018, it requires removing the front bumper cover to access them. You can pick up D3S LED conversion bulbs for way less than $280 for the pair. These work with the factory ballast though, but if the ballast is not the issue, then these can be installed without removing the bumper cover. I installed a pair in my 2018 because my headlights were also dim and fortunately that's all I needed. I had not experienced the flicker.

On my son's Volvo V70R when his ballasts fail there's not even a flicker of the bulb, but his fail due to water intrusion versus just electronics wearing out.

I'm not familiar with the Autel Maxisys Elite, but with my Autel MaxiSys MS906BT I can command the headlights to turn on individually from the scan tool which would bypass the headlight switch. I think there's also a parameter to monitor the light sensor level and whether headlights are requested or not.

If she's willing to spend some money to avoid the dealership bill and you're not ready to give up on it yet, you could start with replacing the bulbs with the DS3 LED drop ins and see if that works before then condemning the ballasts. If it were my car that's where I'd start (after confirming the scan tool does not cause the headlights to light).

-Rod

 

Thank you, Rod.

I'll do some more diagnostics using the Autel tool and see if some inexpensive D3S bulbs make a difference in getting the headlights back on.