Are SClass lighting circuits intelligent?

[PJayUK]

Hi everyone...

I posted a little while ago about changing some of the interior lights in my W220 with LED's as they had stopped working. So I bought some rather nice 12v blue led's from my local Halfords which I installed into the existing front & rear footwell lamp units. The LED's are purpose built and need no resistor so claim to be a simple job of connecting to 12V. After a few days of seeming to work ok, they have started to exhibit an odd behavior. Basically if I switch the headlights on with ignition on but the engine off, the led lights come on for a second or two and then switch off. If I start the engine first and then switch the lights on they work fine.

It looks like there is some form of over or under voltage detection going on or a processor module is getting confused. This all seems rather strange as the original lamps were LED's and the new ones I fitted are only rated at 20ma each which is nothing.

Does anybody know whether the lighting circuits have some form of voltage or current detection?

 

[tromppost]

you do know that if you keep fiddling with the electrics will blow up!

 

[PJayUK]

Damn sneaky these Germans, setting the car to self destruct if the electrics are tampered with!