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Discussion Starter · #1 ·
Greetings-

I am trying to see if I can figure out how to build a resistor/regulator for the HELLA CELIS tail lights for an E39.

I have a 4/1998 production E39, so I think that I cannot simply have the LCM re-programmed for this. (I think it is a second generation LCM, or LCM-2.) If someone knows otherwise, please let me know.

I am curious if anyone has measured the current running through the LEDs, and what the current is (in amps or milliamps).

Also, are the LEDs in a series or are they running parallel?

Thanks in advance.
 

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do you have the nam (us spec) or euro spec celis lights? the easy way to check is to see if you have 4 leds at the ends of the celis bars (which are only on nam spec lights)..


if you have the nam spec then you can just wire the single parking light wire from the celis tails to one of the two parking light wires from the car. if you leave the other parking wire alone you will get a bulb out warning, to fix this you could either get the rear bulb checks removed(programming) or just buy another bulb and wire that in and have it hidden in the trunk; another option is to get another bulb holder and install the 2nd parking light bulb in the rear fog position.
 

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Discussion Starter · #3 · (Edited)
I will be getting the "nam spec" lights.

However, I am somewhat surprised that I can simply plug them in to a 12v line and not burn them up. This is contrary to everything I have read about wiring these up in a car that did not come with them (assuming that changes aren't first made through the LCM).

I am also surprised that I could address the bulb out warning lights on only one of the two parking light bulb wires. There shouldn't be enough resistance from the CELIS lights for you to not have to address the resistance issue for that wire as well.

Thanks
 

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ya the nam spec lights can safely be run with 12v, its the euros that need to be regulated @ 9.7v

ive had the nam spec celis for quite a while w/o any problems.

the leds in the parking light are fine to replace one of the two parking lights our lcm expects, its the other one which throws the bulb out warning.
 

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you can run the nam spec with a voltage regulator like i first did, however you will be under-running the leds and they will be very dim. if you want them im sure i could dig up the regulator schematics i made.

i believe its the 4 leds on the side that they have wired in series with the celis bars which allows us to run 12v.
 

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Performance and life may be more directly affected by current (amps).
Agreed, but ive got about 2 years of use now with my nam spec celis without any resistors or anything and the lights seem to be doing just fine
 

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Discussion Starter · #12 · (Edited)
That is very good to hear. I wonder if the LCM in the earlier E39's regulates the voltage it sends out to the various lights in the car.

That is, it sends out a constant 12v, rather than whatever the alternator/regulator are producing, in the 12.5 to 14.4 range. If not, then some sort of filter or DC to DC converter to regualte this might be a good idea.
 
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