volvo pwm hid issue

Hi,

My 2005 volvo s40, gives a pulse width modulation signal to the headlight bulbs.  I'm trying to upgrade to a 35watt HID kit.

I understand i need a resistor to increase the load to 55watt to remove the bulb warning - which resistor i'm not sure - i've been told i need a 20 watt 17 ohm resistor????

I've also read in here i need to build a pulse/steady circuit to buffer the pulse to a steady 12v.  i've used a bypass cable so the headlight flicks a relay to switch on the balasts, but all this does it click the relay about 20 times a second - hence pulse.  also if i'm using a bypass cable, technically there's no load on the circuit as only the relay is been switched, so i'd need a resistor that has the same power as 55watt to confuse the computer into thinking the bulb is ok.

Can someone tell me which resistors and capacitors i need to build this circuit., i followed someone elses links to radio shack but they did'nt work.

help?

Is'nt 4700uf abit too powerful?

I would prefer to wire directly into stock power connector and run the stable circuit off that.  So if i use 4700uf cap i don't need to use a resistor?  I was going to use a 10uf cap originally, is this not powerful enough?

so....

stocklight pwm > diode > 4700uf cap > output to ballast.

ground straight through to ballast.

Would this work?

thanks

I obtained some 4700uf caps, tried this and still did'nt work.  It stays on for 3 seconds, then just switches off.  I tested the voltage and ecu is actually cutting the voltage.  Least it did'nt flicker anymore.  lol

It is possible that if the stock computer doesn't see the correct load it shuts off the output together.  If you say your stock lamp is 55 watt you will need a ~3 ohm 55 watt resistor to take the place of the head light.  Since you eliminated one 55 watt load and replaced it with another 55 watt load you arn't increasing the load on the electrical system.  You should install this resistor under the hood, away from wiring and what not as it will get hot.  You can find resistors this size at places like Digikey and Mouser.

Theoretically, a PWM signal is an analog signal (more correctly a pulsed digital signal) and you are trying to convert it to a pure digital signal.  You can try the large cap, or you can look in to a frequency switch.  For this application the large cap should be sufficient.

Yeah ok, i'll find a resistor and try again, when it stops raining here in the UK.

I'll let you know if it works.