Headlights Suddenly Shutting Off While Driving

[NeilP]

Just so I'm clear, what "necessary harnesses" are you talking about? Do I need any special cabling to connect my phone with the app to the jeep? Really appreciate all the help.

You need these items: OBDII Diagnostics Scanner, Cable Adaptor for Chrysler 12+8 Programming Cable and (although it's not 100% mandatory but you might as well only slice up your fingers and hands once) Z Automotive SGW Extension Cable

Sponsored

 

[Brendon]

You need these items: OBDII Diagnostics Scanner, Cable Adaptor for Chrysler 12+8 Programming Cable and (although it's not 100% mandatory but you might as well only slice up your fingers and hands once) Z Automotive SGW Extension Cable

thanks!!

 

[Dyolfknip74]

I have a 2021 Jeep Wrangler Willys ordered new from the factory. It came with standard halogen lights. I tried to have the dealer install Mopar LED's when it came in. It installed them but couldn't get them to work because it did not have a code to flash them so re-installed the halogens. I purchased a harness and had a mechanic re-install the LEDS. They seemed to work fine. I rarely drive in the dark except during elk hunting season. Over the past 3 hunting seasons, the lights have suddenly and without any warning shut off. It has happened 3 times in the past 5 times I've driven the jeep. It seemed to only happen after driving for 20+ minutes. They black out for 3 to 5 seconds (although it seems like a lifetime at highway speeds). However, the last time, they went off after less than 10 minutes. There is no flickering or signs of a short or loose wire. Happens on smooth surfaces, paved highways. Turning the light knob on/off makes no difference and does not turn the lights back on -- they just come back on. Any ideas? This is a real safety issue.

Put the stock ones back in until you figure it out if it's a safety issue. If something happens and it's from a mod that was done aftermarket, I'm sure there are liability issues.

 

[cripton805]

I don't understand why you're using a harness. The 21s should be able to run the LED headlights without any resistors or code.

The code is used to turn on the halo. The 18'-20' had to have the wiring kit added to run the halo. The 21s-present came with the halo wiring even if you had Halogen headlights.

 

[cripton805]

Here is another member explaining the same thing.

 

[roaniecowpony]

Sounds to me like the dealership toggled the BCM setting from Halogen to LED, then a harness that has resistors, designed to replicate halogen load, was installed.

If the BCM is seeing Halogen load, but is set to LED, it will cause issues.

You could either leave the resistor harness installed and toggle the BCM back to Halogen, or remove the resistor harness and leave the BCM at the LED setting.

Jscan will allow you to change this setting and many other things, like tire diameter and gear ratio. JSCAN is an app that cost about $25, then you need a Security Gateway bypass harness, and a Bluetooth wireless dongle. https://jscan.net/

 

[Upnarms]

Stop messing around with a harness. As others said, jscan or tazer. I use the tazer mini. Cured all those LED issues and great for at least a dozen other things.

 

[Brendon]

I don't understand why you're using a harness. The 21s should be able to run the LED headlights without any resistors or code.

The code is used to turn on the halo. The 18'-20' had to have the wiring kit added to run the halo. The 21s-present came with the halo wiring even if you had Halogen headlights.

I don't understand why you're using a harness. The 21s should be able to run the LED headlights without any resistors or code.

The code is used to turn on the halo. The 18'-20' had to have the wiring kit added to run the halo. The 21s-present came with the halo wiring even if you had Halogen headlights.

When my jeep arrived at the dealer in September of 2020 it had halogen headlights. The Mopar LED HL were there and were installed and removed with the halogens put back in, all before I left the dealer lot. Surprisingly I wasn't charged for the installation/uninstall/reinstall. I was told they did not have the codes to make the LED's work properly. They said it was a factory issue that was not yet caught up with. So I'm really confident that they were re-set for the halogens rather than the LED's. I ended up with the harness because, at the time, it seemed like the only way to have the LEDS. I'm going back to OEM connectors and the halo wire with a scan in the hopes that does the trick and the HL stay on all the time.

 

[Brendon]

Sounds to me like the dealership toggled the BCM setting from Halogen to LED, then a harness that has resistors, designed to replicate halogen load, was installed.

If the BCM is seeing Halogen load, but is set to LED, it will cause issues.

You could either leave the resistor harness installed and toggle the BCM back to Halogen, or remove the resistor harness and leave the BCM at the LED setting.

Jscan will allow you to change this setting and many other things, like tire diameter and gear ratio. JSCAN is an app that cost about $25, then you need a Security Gateway bypass harness, and a Bluetooth wireless dongle. https://jscan.net/

Which

Sounds to me like the dealership toggled the BCM setting from Halogen to LED, then a harness that has resistors, designed to replicate halogen load, was installed.

If the BCM is seeing Halogen load, but is set to LED, it will cause issues.

You could either leave the resistor harness installed and toggle the BCM back to Halogen, or remove the resistor harness and leave the BCM at the LED setting.

Jscan will allow you to change this setting and many other things, like tire diameter and gear ratio. JSCAN is an app that cost about $25, then you need a Security Gateway bypass harness, and a Bluetooth wireless dongle. https://jscan.net/

Which bypass harness and Bluetooth wireless dongle do you recommend? Thanks for your help!

 

[roaniecowpony]

Here's their list of recommended dongles. Supported and Not Supported OBD Adapters – JScan

I went with one of the recommended dongles Amazon.com: Vgate vLinker MC+ Bluetooth OBD2 Car Diagnostic Scan Tool for iOS, Android & Windows : Automotive

This is the SGW bypass harness I'm using. Amazon.com: TTXSPP Cable Adaptor for Chrysler 12+8 Programming Cable Connector for Autel DS808 Maxisys Main Test Cable for Autel DS808 Maxisys MS905 MS906 MS906BT MS906S MS908 MS908S Pro : Automotive

 

[Brendon]

Here's their list of recommended dongles. Supported and Not Supported OBD Adapters – JScan

I went with one of the recommended dongles Amazon.com: Vgate vLinker MC+ Bluetooth OBD2 Car Diagnostic Scan Tool for iOS, Android & Windows : Automotive

This is the SGW bypass harness I'm using. Amazon.com: TTXSPP Cable Adaptor for Chrysler 12+8 Programming Cable Connector for Autel DS808 Maxisys Main Test Cable for Autel DS808 Maxisys MS905 MS906 MS906BT MS906S MS908 MS908S Pro : Automotive

Great! I'm going to get things ordered today.

 

[Swagger]

I swapped the halogens with OEM LEDs. I had the tazer and set them to LEDs, and they worked great. Needed warranty service, so unmarried the tazer, and the Jeep was dangerous to drive at night. Pass side was turning on and off, and the low beams were dimmer, and when the high beams were switched on, the low beams shut off, leaving a big gap in the light pattern. Get that code changed, get a tazer, or swap back to the halogens until you get this worked out.
I went the Tazer route, because Rubicon and lots of improvements/ settings can be changed, but only you can judge if the coin is worth it.

 

[Brendon]

I swapped the halogens with OEM LEDs. I had the tazer and set them to LEDs, and they worked great. Needed warranty service, so unmarried the tazer, and the Jeep was dangerous to drive at night. Pass side was turning on and off, and the low beams were dimmer, and when the high beams were switched on, the low beams shut off, leaving a big gap in the light pattern. Get that code changed, get a tazer, or swap back to the halogens until you get this worked out.
I went the Tazer route, because Rubicon and lots of improvements/ settings can be changed, but only you can judge if the coin is worth it.

Thanks for the input. I plan on going with JSCAN for this issue because I'm not planning any more upgrades or mods that will require a scanner. Although, I am seriously looking at re-gear to 456 now that I'm out of warranty.

 

[Swagger]

Yeah, most go with either jscan or Tazer. I think both work fine. Lately I've been using the tazer more to read and reset cel codes unfortunately. I think if you are going to do any kind of mods you need one or the other.

 

[Brendon]

Yeah, most go with either jscan or Tazer. I think both work fine. Lately I've been using the tazer more to read and reset cel codes unfortunately. I think if you are going to do any kind of mods you need one or the other.

UPDATE - went back to the original set up with the halo wire. Used JSCAN to reset everything to LED. So far, everything working fine although I have not driven over 20 minutes in the dark.

Sponsored