# New LED bulbs won’t turn on **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [March 22, 2020, 10:15am UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502 "2020-03-22T10:15:13Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Diarmuid\_Gallagher](https://avatars.discourse-cdn.com/v4/letter/d/3da27b/32.png) [@Diarmuid\_Gallagher](https://community.cartalk.com/u/Diarmuid_Gallagher)\ **Post date:** [March 22, 2020, 10:15am UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/1 "2020-03-22T10:15:13Z")
Hi guys just wondering does anyone have any tips that could help me? I’ve just installed two new LED low beam headlights and when I switch them on in the car the turn on for 1 second then cut out and I get a message on the dash saying Low beam fault… any ideas please?? ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [March 22, 2020, 10:32am UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/2 "2020-03-22T10:32:29Z")
Did your Focus come with LED bulbs? If not, I see they sell conversion kits to change from halogen so I don’t think you can just swap bulbs. ---
**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\ **Post date:** [March 22, 2020, 10:34am UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/3 "2020-03-22T10:34:06Z")
I didn’t think a 1903 Oldsmobile Curved Dash even had an electrical system capable of supporting headlights. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [March 22, 2020, 11:40am UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/4 "2020-03-22T11:40:42Z")
Can’t remember if it used oil or kerosene for the headlights. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [March 22, 2020, 1:04pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/5 "2020-03-22T13:04:23Z")
> [@Purebred](#): > > Can’t remember if it used oil or kerosene for the headlights. The cars of the early 20th Century usually used acetylene to power their headlights. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [March 22, 2020, 1:07pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/6 "2020-03-22T13:07:42Z")
> [@Diarmuid\_Gallagher](#): > > I’ve just installed two new LED low beam headlights and when I switch them on in the car the turn on for 1 second then cut out and I get a message on the dash saying Low beam fault… any ideas please?? Yes I have an idea . Just put in what your owners manual says what the bulbs should be . ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [March 22, 2020, 2:07pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/7 "2020-03-22T14:07:40Z")
You will need a conversion kit (if there is one for your car). Just replacing the bulb will blow it in a second. The kit contains the appropriate electronics, i.e. resistors, to keep the bulb from blowing. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [March 22, 2020, 2:10pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/8 "2020-03-22T14:10:59Z")
We’re dealing with LED bulbs, not HID. Many aftermarket LED bulbs plug right in. These sound like they’re defective or just low quality. I’d return them and go back to high quality halogens. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [March 22, 2020, 2:33pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/9 "2020-03-22T14:33:57Z")
> [@Diarmuid\_Gallagher](#): > > I’ve just installed two new LED low beam headlights and when I switch them on in the car the turn on for 1 second then cut out and I get a message on the dash saying Low beam fault… any ideas please?? Throw these cheap Ebay LED lights way and return to the proper bulb for the car. Problem solved! ---
**Author:** ![old\_mopar\_guy](https://avatars.discourse-cdn.com/v4/letter/o/6bbea6/32.png) [@old\_mopar\_guy](https://community.cartalk.com/u/old_mopar_guy)\ **Post date:** [March 22, 2020, 2:40pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/10 "2020-03-22T14:40:17Z")
Maybe acetylene “pres-to-lite”. ---
**Author:** ![NYBo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nybo/32/17281_2.png) [@NYBo](https://community.cartalk.com/u/NYBo)\ **Post date:** [March 22, 2020, 5:48pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/11 "2020-03-22T17:48:24Z")
Your car is “smart” enough to be fooled by the low current usage by the LEDs into thinking the bulbs a blown. It then shuts down the circuit and gives the error message. You need to install load resistors to fool the car into thinking there are regular halogen bulbs installed or purchase better LEDs that are properly compatible with a modern car. ---
**Author:** ![dwilllemin\_164289](https://avatars.discourse-cdn.com/v4/letter/d/ee59a6/32.png) [@dwilllemin\_164289](https://community.cartalk.com/u/dwilllemin_164289)\ **Post date:** [March 23, 2020, 7:25pm UTC](https://community.cartalk.com/t/new-led-bulbs-won-t-turn-on/161502/12 "2020-03-23T19:25:29Z")
NYBo hit the nail on the head! You’ll have similar problem if your car has regular tail light bulbs and replace them with LEDs. Adding risistors defeats the energy savings of the bulbs and if they are located on/in the bulbs will shorten the life due to the heat they produce. I installed LED tail and parking in my old van but it was and easy fix to replace the flashers, The best fix to use LED head lights in your car would be to somehow get the computer reprogrammed to accept the lower current bulbs but that may not even be possible.