Rear LED lights

[OdinEidolon]

Hi all folks!
Disappointed by the amount of light emitted by the rear reverse lights on my saloon I decided to install new LED lights back there. Also brake/position lights as I was there already.

Got a couple of Crees Q5 for the reverse, they are blinding, really powerful. The problem is that the car for some idiotic reason sends power through them even when they are off. So when they should not be lit they light up intermittently for ~0.1 secs with a period of maybe ~0.2secs. While this is not annoying for those behind since the emitted light in the short period they are on is not much, I fear some cop could pull on me because of that. Of course this is not a problem with normal incandescent lights.
I think I should put a capacitor in parallel with the lights or a resistor in line with them. I do not know if the sencond one will work since it'll lower the working voltage of the LEDS which are designed to run at 12V. EDIT: this happens only with the car turned on. If only ignition is on then it's fine!

I also put some good red LEDS for the rear stop / position lights. They look good, but there is a strange problem. Here I list what happens with and without the LEDS:
POSITION LIGHTS ON, BRAKES OFF
With LEDs the inside light lights up in the low position and the exterior light does not light up. With incandescent bulbs both light up in the low position.
POSITION LIGHTS ON, BRAKES ON
With LEDs the inside light lights up in the low position and the exterior light lights up in the high position. With incandescent bulbs both light up, one in the low and one in the high position.

Any ideas why this happens and how to fix?

Also, I broke one of the screws holding the headlight in place when refitting them. Servicebox is not of help. Do you think I could fit a new one? And where to grab it? Dealer?

[RayneR]

You could sort all that if you bought can-bus lights that prevent from doing that, these incorporate the resistor/capacitor.

[OdinEidolon]

You could sort all that if you bought can-bus lights that prevent from doing that, these incorporate the resistor/capacitor.

Yeah but I did not. Since the 406 has nothing of the modern "lights malfuncioning" "features" some cars now have I dd not feel the need for it. By the way there's absolutely no reason to why they should behave like this. Why feed the reverse lights (and those only) with 12V current even when off (the lights not the car), just with a very small lighting period? It makes no sense! Also this happens only when the car's running, not on ignition, so I'm starting to think this is an electrical problem more than an unwanted feature.

[RayneR]

Maybe you're right, i also have something strange.

When i engage reverse, my parking sensors turn on and works ok, but if i turn on the rear wiper, the parking sensors beeps " 0 meters " like i hit a wall, and stops right after the rear wiper stops. Also something similar happens when it rains there is some days that they do the same even without turning on the rear wiper.

Anyone had this problem ?

thank you.

[Doggy]

I think you should both check the integrity of the common earth connection to each lamp assembly.

Adriano, it would be interesting to try fitting one normal reversing light and one LED - I suspect the LED will then work correctly.
If it does, the answer is probably a resistor, connected in parallel wih the reversing lamps to emulate the load of a filament lamp and discharge any leakage / induced voltage so it doesn't light the LEDs.

[OdinEidolon]

Maybe you're right, i also have something strange.

When i engage reverse, my parking sensors turn on and works ok, but if i turn on the rear wiper, the parking sensors beeps " 0 meters " like i hit a wall, and stops right after the rear wiper stops. Also something similar happens when it rains there is some days that they do the same even without turning on the rear wiper.

Anyone had this problem ?

thank you.

I fear noone here has got parking sensors so...

I think you should both check the integrity of the common earth connection to each lamp assembly.

Adriano, it would be interesting to try fitting one normal reversing light and one LED - I suspect the LED will then work correctly.
If it does, the answer is probably a resistor, connected in parallel wih the reversing lamps to emulate the load of a filament lamp and discharge any leakage / induced voltage so it doesn't light the LEDs.

I did not try to be honest. I tried only with the car off, and that was fine, except for the rear position lights / stops still behaving strangely as described in the first post. But that is OK, since they still do their job.
I'll check the earth. Any idea which cable it is? I think the best bet would be fitting a decently sized capacitor in parallel, to lower the voltage spikes. Also a resistance in parallel would work, provided that it's decently sized and does not upset the BSI (I'll have to find out the resistance of the LED to find out how much I need) but that would still mean wasting that little amount of energy that for some reason travels through the circuit.
Tomorrow I'll check a bit more carefully with the multimeter in one hand and a pencil in the other.