LED lights on an old rig (2008 Wrangler jku)

[Alex Brame]

In April of this year I bought a 2008 Jeep Wrangler four door 'X" model. I've been upgrading the old guy since, as well as making the necessary repairs and fixes that crop up.
Recently I decided it was time to upgrade the stock headlights with LED headlights, and the list of issues has begun to grow. No problem with the main headlight function, probably because the wiring harnesses included "power rectifiers", whatever that means ;). No the problem is that I bought some of those headlights that have halos, dual function halos. Supposed to come on as DRLs (daytime running lights) but a 2008 wrangler doesn't have 'em. So I thought I'd wire them to something else...that works, but the turn signal function does not. To make matters worse, I got LED turn signal lights, and they don't work at all. Someone told me I needed to add resistors, but I haven't found a product yet. Hmmm... I plan to upgrade the tail lights and fog lights similarly, but I wonder if I'll have similar problems. Better to avoid LEDs?

 

[RoarinRow]

I replaced my headlight housings and bulbs to HID and LEDs all except for the turn signal bulbs. Those I left at halogen lights because of the same issues about rapid flashing or the need for resistors. For tail lights I would also leave those as halogen bulbs, but fog lights should be ok to change to LEDs. I replaced by bulbs in my tail lights to LED before and it wasn't as bright as regular halogen bulbs. I am guessing because the halogen lights are round shaped and fill the space inside of the tail lights.

 

[madcratebuilder]

I've converted all lighting on my 17 GM truck to LED, I had to add resisters to the front and rear TS. Resisters can be found on amazon dirt cheap.

 

[Jedi]

There are two problems you will run into when upgrading to LED lighting.

• The first problem is due to the CANBUS monitoring of the circuit. The system utilizes the resistance on a circuit to identify a fault. With an LED bulb, the resistance is much lower than the CANBUS is expecting, so it throws an error (in the case of turn signals, this is manifested as the "hyper flash"). This problem is resolved by introducing resistance (via a resistor) into the line.
• The second problem is due to the use of modulated power. My understanding is that this exploits the slower discharge rate of gas filled bulbs and is done to extend their life expectancy (less time at voltage). Unfortunately, LED lights are instantaneous and will flicker in sync with the modulated power. To resolve this, a capacitor is installed to allow for a constant voltage.

When looking at replacement lights, it is important to keep these two problems in mind.

For my headlights, I built a complete wiring harness that included a new relay, capacitor, and resistor. While this was partially due to the need to replace the harness as a result of rodent damage to the existing one, this has set me up to be able to do the same for my turn signals, fog lights, and tail lights. Doing this is not for the faint of heart or those who are not familiar with wiring.

 

[Alex Brame]

There are two problems you will run into when upgrading to LED lighting.

• The first problem is due to the CANBUS monitoring of the circuit. The system utilizes the resistance on a circuit to identify a fault. With an LED bulb, the resistance is much lower than the CANBUS is expecting, so it throws an error (in the case of turn signals, this is manifested as the "hyper flash"). This problem is resolved by introducing resistance (via a resistor) into the line.
• The second problem is due to the use of modulated power. My understanding is that this exploits the slower discharge rate of gas filled bulbs and is done to extend their life expectancy (less time at voltage). Unfortunately, LED lights are instantaneous and will flicker in sync with the modulated power. To resolve this, a capacitor is installed to allow for a constant voltage.

When looking at replacement lights, it is important to keep these two problems in mind.

For my headlights, I built a complete wiring harness that included a new relay, capacitor, and resistor. While this was partially due to the need to replace the harness as a result of rodent damage to the existing one, this has set me up to be able to do the same for my turn signals, fog lights, and tail lights. Doing this is not for the faint of heart or those who are not familiar with wiring.

Thank you master Jedi! I'm not afraid to try. Just managed to complete some things: dual battery setup with an isolator relay followed by an Spod for switch accessory lights, etc.

 

[M Rose]

Simple fix, get an electronic turnsignal flasher from your local parts store and replace the oem flasher, then your turnsignals will work. for the DRL, you need to wire them up to a ignition on hot wire.... I usually tap I to the radiopower wire and run the wire tap to pin 85 of a 5 pin relay, then pin 86 to ground, pin 87 hot from battery, and pin 30 o drl hot.

 

[Alex Brame]

I've converted all lighting on my 17 GM truck to LED, I had to add resisters to the front and rear TS. Resisters can be found on amazon dirt cheap.

They seem to all say that they get really hot. Is that anything to worry about?

 

[Alex Brame]

Simple fix, get an electronic turnsignal flasher from your local parts store and replace the oem flasher, then your turnsignals will work. for the DRL, you need to wire them up to a ignition on hot wire.... I usually tap I to the radiopower wire and run the wire tap to pin 85 of a 5 pin relay, then pin 86 to ground, pin 87 hot from battery, and pin 30 o drl hot.

Thanks!

 

[madcratebuilder]

They seem to all say that they get really hot. Is that anything to worry about?

They do get hot, do not mount to plastic panels. You can buy ones rthat have large heat sinks at about 10 bucks each.

 

[Alex Brame]

Thanks to all who offered advice to this ...mature beginner at a Jeep build. your advice was very helpful, and though it took me a long time to reason it out, all is installed and working.

 

[M Rose]

Those look nice, glad you got it all sorted out

 

[Alex Brame]

Those look nice, glad you got it all sorted out

There were some confusing aspects, LEDs on an older rig. The headlights included halos, supposed to go on DRL circuit. But my rig does not have DRLs. So I tried to put them on with the park/running lights, and that led to more problems. In the end it was the TIPM that didn't like this, so I stuck the halos on an auxiliary switch (for now) which works well enough for me to use like a DRL. Weird, huh? Everything got upgraded to LEDs except the turn signals/side markers. I decided it wasn't worth the frustration, and they were working just fine as is.