I have recently bought a new car and replaced the number plate bulbs with leds. The Leds work; however when the lights are switched off, the car does it's own electrical check of all the bulbs by sending a pulse down the particular line.
With normal bulbs, this doesn't do anything but the leds flash.
I have came across a video where someone used a 12 V relay to fool the car when it's doing its self check, but he had to leave the bulbs connected to this circuit which he then fixed behind some interior trim.
I don't want to be driving around with bulbs knocking around behind trim panels, so was going to use a resistor in their place.
I'm having trouble with deciding on the value of the resistor.
The bulbs are 12 V, 5 W and gave a resistance of 3.5 Ω. There are 2 of them wired in series.
So would I need a 7 Ω 10 W 12 V Resistor?
Or a 7 Ω 5 W 12 V Resistor?
Or would I be better with some sort of diode?
Or am I way off with it all?
The vehicle diagnostic does its check on cold bulb only. I want a Resistor that will mimic the cold bulb. Once the lights are switched on and they get a full 12 volts the relay will come into play and divert power to the leds which work no problem. Issue only occurs when lights are off