Relay problem

[raj55]

I have connected a pair of day time driving LED lights via a relay and for some reason when I switch on my low beam or parking light the DRL shuts off as it should BUT the relay emitts a loud and disturbing chattering noise. As far as the connections go I have taken the switching current (the one that flips the relay so that the current to the DRL is cut off) from the parking lamp wire (going to BMW's rings-angel eyes lamps).
I have never heard a relay make that noise before. I can even feel the relay vibration on touch. Is the Hella's new relay bust or is there some kind of alternating current that is making it vibrate and chatter? The light is working as it should but the vibration and the sound is too much. Please help.
Thanks in adbvance,
Raj.

[Scheinwerfermann]

You don't say what year and model BMW you're working on, but many BMWs produce the parking light function by applying reduced voltage (via PWM) to the front turn signal filaments or, on more recent models, to the DRL angel eyes. It sounds like the parking lamp wire you tapped to open the DRL relay sees pulsed voltage when the parking lamp function is selected. This will kill the relay in a fairly short time. You might try putting a capacitor across #85 and #86 of your relay and a diode between the #86 and the trigger wire that feeds it, along the lines of what the late-model Jeep owners do to install relays in their PWM headlamp circuits.

[uffstuffson]

I second Scheinwerfermann if that is a PWM circuit. Another thought if it isn't pwm is possibly just a ripple in the dc wave from a cap going bad or a bad spot on an alternator brush. Does the vehicle have alternating corner marker lights when the turn signal/hazards are operated?

[Scheinwerfermann]

Does the vehicle have alternating corner marker lights when the turn signal/hazards are operated?

BMW's never done that.

[raj55]

This is a BMW E91, 2009 year model with halogen lights and angel eyes. The angel eyes are not connected as day time lights in this model. The low beam is the DRL in Sweden. The angel eyes only come on when the parking switch is activated (i.e. the angel eyes are then parking lights) or when the low or high beam are activated (the angel eyes then shine less brightly along with the low or high beam). I think that Scheinwerfermann is correct in his assessment. I'll have to attach a capacitor and a diode but what values? I'll certainly look at the link you suggested.
On second thought I should perhaps connect the relay to the wire going to the low beam (if it is not pulsed), instead of the angel eyes. Would that solve my problem? I want the LED DRL to shut when I put on low beam or high beam lights.
Thanks again.
Raj.

P.S. Sorry for jumping the gun, I see that the referred site has the values for the capacitor and the diode. I'll have to look in my old Tube amplifier box for the parts mentioned. Thanks.

[raj55]

I would be most grateful if some one could explain to me if the diode in that circuit is really necessary if the current is a pulsating DC. Having looked at certain other sites where people seem to use only the capacitor to get rid off the flickerring nature while connecting the trigger wire to the relay. Perhaps I am missing some thing here.
Raj.

[Scheinwerfermann]

The angel eyes only come on when the parking switch is activated (i.e. the angel eyes are then parking lights) or when the low or high beam are activated (the angel eyes then shine less brightly

If the angel eyes really have two levels of intensity, then something's amiss. Are you sure this is the case? If so, check and see what kind of bulb is used to light your particular car's angel eyes. Is it an H8, or something else? I ask because it begins to sound as if your car's lighting operations are not configured quite as they ought to be, which is a matter of body computer programming.

[raj55]

I read in a BMW forum that it is a two intensity level angel eyes but I am not sure what sort of bulb they have. The halogen model car and the HID model car have different types of halogen angel eye bulbs. I think the H8 bulb in the angel eyes only applies to the car with HID low/high beam.

[Scheinwerfermann]

No good. Go find out what is on/in your car. You can't read that off the internet, you need to go down to the garage/driveway/parking lot and see for yourself.

[raj55]

You don't say what year and model BMW you're working on, but many BMWs produce the parking light function by applying reduced voltage (via PWM) to the front turn signal filaments or, on more recent models, to the DRL angel eyes. It sounds like the parking lamp wire you tapped to open the DRL relay sees pulsed voltage when the parking lamp function is selected. This will kill the relay in a fairly short time. You might try putting a capacitor across #85 and #86 of your relay and a diode between the #86 and the trigger wire that feeds it, along the lines of what the late-model Jeep owners do to install relays in their PWM headlamp circuits.

Thanks Scheinwerfermann,
Just connected the relay as shown in your post and it works! I was careful with the polarity and connections and did not blow any capacitor. I am all legal with the new DRL laws in Europe now. Thanks again.
Raj.