Anyway around this

[BadBm_ 3]

I changed my number plate lights to led ones (I work at brightlight led solutions so free led) it looks great but I have warning light pop up on my dash every time I start my car. I've been told why and stuff why it's doing it but anyway around it?

BMW e90

[aja540i 1903]

You need to change the resistance of the leds so the computer thinks there is a light bulb there. Im not sure if you can recode it so it doesnt check for number plate lights, but its probably easier to put a resistor in series with the led bulbs so it knows they are there.

[polley 916]

In series will reduce current through the led and make it dimmer. Pretty sure it should be in parallel. I could be wrong though

[gjm 3194]

[elmarco 56]

Be warned that doesn't always work - the more sophisticated systems look for the correct current draw (over time) of a filament which is difficult to simulate with a resistor. You may also see the LEDs pulsing (even with the lights off) depending on the electronics & the LEDs.

[polley 916]

Be warned that doesn't always work - the more sophisticated systems look for the correct current draw (over time) of a filament which is difficult to simulate with a resistor. You may also see the LEDs pulsing (even with the lights off) depending on the electronics & the LEDs.

That can be calculated, and then correct resistor installed. Will draw same current as original bulbs.

Bit harder to stop the pulsing though. May as well just disable the checks if possible, as they won't pick up a failed led with the resistor installed in parallel anyways.

[elmarco 56]

That can be calculated, and then correct resistor installed. Will draw same current as original bulbs.

Sure, but as I said it isnt that simple for systems that look for the correct rise time in current draw for a filament (no idea if the E90 is like that but they are out there - I think Volvo was one). This is quite different to a dumb resistor - we spent a lot of time trying to fool these systems when I was at Hella & ended up with plugin electronics or a bunch of electronics inside the lamp. In extreme examples, the dumb resistor wouldn't fool the system which would then assume no trailer was attached to the truck, and not release the trailer brakes....

[polley 916]

Did you guys ever figure out why your led lights on the new ambulances kept crapping out in under a week?

[aja540i 1903]

In series will reduce current through the led and make it dimmer. Pretty sure it should be in parallel. I could be wrong though

You can actually do it either way, it will just be a much higher value resistor in parallel than if you put it in series, as long as the total resistance of the led and the resistor is the same, or similar, to the filament type bulb it should work.

Obviously if the resistor is too big it will dim the led but they use such a tiny amount of power it doesnt have to affect the brightness.

[elmarco 56]

Did you guys ever figure out why your led lights on the new ambulances kept crapping out in under a week?

No idea - never heard of problems on ambulances while I was there.

[kiwi328i 118]

Lots of errors in the dialogue above.

1) Incandescent lamps have a low cold resistance which increases as they heat up so current is high to start with and drops off ( commonly referred to as inrush current)

A resistor cannot emulate this - electronics can.

2) The monitoring is typically looking for a current that is in a range example a 12watt lamp will draw 1 amp so the range might be 0.8 to 1.2 amps , It may include a window for the inrush current.

3) Putting a resistor in series will only REDUCE the current which is generally the opposite of what is required as LED lamps draw less current than incandescent.

Two benefits of LED lights are reduced power use and longer life, slapping a resistor in parallel to fool the monitoring eliminates the first benefit.

I think the Op is looking for a solution. What can we as observers deduce from this? I have been thinking about putting in LED's into my ole beast so I would also like to know if there is a solution to this, if I encounter the same issue. He is asking "...anyway around it?"

Cheers

[BMTHUG 943]

You can get the one's with built in resistors from ebay. I have ordered them before and they work a treat. Not sure if you have festoon bulbs though

[Michael. 2312]

Could always cut the warning light wire if there is a tail light control module. Probably isn't one though.

[polley 916]

Just turn off bulb checks if possible

[allan 295]

As Troy said turn off the bulb check function it can be done for various bulbs in the e46 so why not the e90

http://www.horizonleds.co.uk/bmw-e90-e91-e92-interior-led-kit

Edited May 12, 2015 by tim 325

[M5V8 337]

replace LED blub with one that guarentees "euro error free" (ie- has correct resistor already installed)

[polley 916]

replace LED blub with one that guarentees "euro error free" (ie- has correct resistor already installed)

Nooooo, we cant use the resistor, we are trying to save gas!

[_ethrty-Andy_ 2122]

The unstated way round is simply not to do it and just fit good quality OE type lamps.

my guess is the OP is wanting to upgrade from earlier style housings to later style ones, the former using incandesents and the latter using LEDs. for example when people fit E46 M3 taillights to non-M3

[polley 916]

its a lot of forum dialogue  for a pair of number plate lamps don't you think.??

 

imagine how many Photons , water molecules and bags of coal have powered the servers that have allowed this debate to take place, more than  the number saved by installing the LEDS in the first place ?

Can't be any worse than the amount used for hosting child pornography or any other pointless drivel posted on forums.

[BadBm_ 3]

Hey everyone thanks so much for your guys input.

Good news is no more warning light resistors did the job