Resistors for LED Tail Light Conversion
 

Question: is the tail light monitoring system only for the stop filaments or does it include the parking lights filaments on one or both tail light bulbs?

thanks in advance for making my resistor calculations easier.

WhiteHat….…….

Resistors are required for the Blinker Light (Use Amber Bulbs)…...Also the outside Rear-Light/Stop-LIght (1157 Red) Continue using the (Clear)1157 Bulb in the Middle Red light as the Lens is made differently and uses only a regular 1157 Bulb.(No LED). The English Fog-Light uses a (Red) 1156 LED and the Back-up Light uses a 1156 Clear Bulb. Neither of which has to have anything done as they are not hooked-up to the CAMBus system.....I use those clear Magnified LED Bulbs as my Back-up's and they work great as do the (Red) 1156'sLED's that go in the Fog Lights...

Billy Clyde

thanks Bill, is it that both filaments in the outside Rear-Light/Stop-Light are monitored and nothing of the middle 1157? not changing the blinker or fog light. with the latter it is possible for such lights to be too bright in the fog, and where i travel it gets really thick sometimes. actually converted my fogs to yellow for this reason.

bcprice36
What value resistor? and how is it wired into the tail-light assembly?

for the stop light a 50W/6Ohm resistor wired in parallel with the filament. i am trying to figure out if a resistor is needed for the parking light filaments, for the outside and/or inside bulbs.

Here is a good video on LED modifications.

There are no resistors needed for the park lights, but there does seem to be some small amount of current still applied to them once you shut the car off and before the SLM goes to sleep. Not enough to make light in a standard bulb but is with an LED. This leads to a creepy low level glow in a dark garage.

Can be resolved by using the so called CANBUS bulbs that have a small pull down resistor built into them.

Hi Cor,

I'm in contact with 4sightlighting in UK. They have just developed a tail/stop led with canbus adaption so there will be no need for resistors.
They will send me 4 samples to try on my XKR 2002 and if they do the job i will keep you informed. Normaly a resistor 25 ohm wil be ok.

regards
Walter

Rear tail lights and stop lamps are both monitored. 2001 up with two tail lamps on each side which are monitored as a pair (i.e.10W total per side).

Not sure on this, but the rear side markers and number plate lamps may also be.They aren't on pre-2001 cars, although JTIS implies otherwise.

thanks, i plan on using the Phillips bulbs described in the video that was just linked above to this thread. they have the correct layout of diodes for the reflector and Phillips also has a ready made resistor kit for the bulbs. my issue is only whether the park lights filament needs to be monitored. my goal is that if it is on constantly, it is LED. guess that I will find out soon.

thank you for the information. when i complete the install the experiment will show what happens. for the parking filaments it might be easier to simply find the common hot on the harness and install a single resistor. same could also be done for the stop lights. everything is in parallel.

thanks for posting the video. i plan on using the same bulbs as the video author. however i majorly disagree with the concept of making the rear fogs into the brake lights. if one never uses them as such, it is a novel idea. the problem is that if one is using the rear fogs as such, then the extra brightness prohibits seeing the stop light/tail lights becoming brighter when braking. i deal with fog and misty roads. a blinded following driver who does not know that the car is braking is a problem.

Mark,

Charlie Fulton did this LED Tail Light idea some time ago...all I have done is follow his directions...As I said, the only lights that need dumbing down are the Blinkers and the outside Brake/Tail Light....He did this with little resistors that are soldered to span the Traces. He has all the directions ….Once again, the Back-up and the English Fog Light are free from the CANBus system and all you do is screw-in the LED Bulb for that socket.....1156 LED "Red" for Fog Light and a "Clear" or Magnified LED for the Back-up Lights...SuperbrightLEDBulbs has an LED Bulb that looks like a Flower, which I tried...Problem with those is the reflectors in the Tail Lights can't reflect the entire Bulb as it shines to the rear....looks petty good until you put in one of the Lumen NB Series Bulbs that shine all around inside the reflector and really lights it up......It's beautiful! really makes things look good day or night... Don't use a white bulb with a Red Lens....use Red...it's brighter...
It's fun Guys…..I use the English Fog Light (with Red Bulb) during the Winter.....It's great fun to reach over and turn-on Fogs when some Pickup driver comes up behind you with his Bright's on....You know what I mean as their LED's or in some cases HID's shine right into your mirror....with the Brake and Fog lights both on you can get them to "Dim" those babies down.in a hurry!

BC

Walter,

All this sounds good, so long as they are designed to fit the 2003 - 2006 Tail Lights... The earlier Lights have different connections than the later Models and would have to have a different type connector....or maybe re-wired....

Let us know more about these samples, as you never know what someone will come up with.....

Billy Clyde

Victory Edition with LED Bulb set-up
 

This is what it looks like after all the work! As I said, the Outside Brake Light is an 1157 LED and the Middle Bulb is a Regular 1157 Halogen....because the Middle Bulb is behind a different looking reflector it can't put out as much but this one uses the extra Bright Halogen Bulb it helps lighter up anyway.....Notice how the LED reflects off the Victory Lens.....really lights up everything.....
https://cimg1.ibsrv.net/gimg/www.jag...d3401b987d.jpg
LED 1157R Outside Bulbs with Extra Bright 1157 Halogens in the Middle Lens. The Outside LED are just ON as or the Halogens....

UPDATE: the filaments for the parking lights in the taillights are monitored including the secondary redundant taillights in the center. the choice is either resistors or modify the PCB. the rear sidelights are not monitored, nor the front.

does anyone know of an led that fits in the license tag fixtures. my bulbs are a little too long.

on another note, does anyone have a right side headlamp dipped (low) beam reflector that he would like to sell. when i figure out how to upload pictures of my dreadful fix, you can see my mess up.

Sorry, I was not following the terminology you were using, I was referring to the marker lights and side repeaters for the weird creepy glow. You are correct, the rear tail lamps and brake lamps are both monitored independently.

Turn signals are monitored as well, although in a different way. No error message will appear but the interior noise maker will go double time if a bulb is out or an LED has not enough internal resistance. This was confusing the first time I encountered it because the noise is double speed but the exterior flashing is as normal. I guess the idea was to emulate what would happen with a conventional mechanical relay and expect that people would know what that meant?

Depending on model year the monitoring circuits are either in the security locking module (indicated in the wiring diagram by the dotted symbols inside the SLM) or as a stand alone monitor unit. The circuit to do the actual monitoring is the same in either case.

The short of it is that there is a fixed resistor in line with the bulb and the comparitor is measuring the voltage drop across that resistor. If the current is too low, then the voltage drop is too low and the comparitor flags a "bad bulb". You don't really need to match the resistance of the bulb exactly but getting a resistance that doesn't trip the limit can be a little fiddly.

I suppose one other option would be to modify the resistors in the monitor circuit to be more appropriate for LED bulbs... or disable the output from the comparior so that there was never a failure message no matter what happened.

https://cimg7.ibsrv.net/gimg/www.jag...ed9956b979.jpg

https://cimg7.ibsrv.net/gimg/www.jag...d78ab5538c.jpg

@ccfulton -- Charlie thank you for the wiring diagrams. very much appreciated.