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Aussie201 · 09-02-2012, 19:17

Hi there,

I am in the process of wiring a set of new Daytime running lights to my Mercedes. However, I am wiring them for 2 purposes.

Firstly to switch on when my interior lights switch on ( Wired to the Interior lights circuit) when I unlock the car, and secondly, to switch on when the car sidelights are switched on ( sidelight circuit).
I've wired up all the relevant wires and thought everything was sweet untill I tested it out.
When the interior lights illuminate the relay buzzes quite loudly for a second. Same happens when they fade off. My guess is that the relay is making the noise because it's not getting enough voltage during the on and off sequences.
All wire connections/ground cable are good

Does anybody know how I might be able to stop the buzzing??

Plug · 09-02-2012, 20:16

Do the interior bulbs come on gradually and go off gradually? If so they must be an electronic resistor changing that circuits resistance, what year/car is it, I might be able to get a diagram.

Aussie201 · 09-02-2012, 20:31

Yes they do. It's a 00 Mercedes A 160

Plug · 09-02-2012, 20:38

Is it the front one you have it wired to and are they three bulbs in it?

Plug · 09-02-2012, 20:49

If thats the one, follow pin 4 with a grey/blue wire, look inside the light unit and there may be a little capacitor and diode. try remove that but obviously complete the circuit in the lamp unit.

Aussie201 · 09-02-2012, 20:53

What would the outcome be after I remove the capacitors? I'd still like to have the fade on/fade off effect when opening the doors.

langdang · 09-02-2012, 21:55

Plug, is the power coming straight from accessory, or is coming via a control module or a relay? There is hopefully a steady 12v somewhere.

Plug · 10-02-2012, 13:42

The 12v that comes out of a control module in the instrument cluster. That is timed to turn on when the doors are opened and go out when you lock up/walk away after a set amount of time. The capacitor is on that circuit inside the lamp and if you remove it you wont have that fade effect. I don't think there is much you can do unless you make a parallel circuit, one for the lamp with capacitor and the other for the day time lights.

09-02-2012, 19:17	#1
Aussie201 Registered User Join Date: Feb 2008 Posts: 71 Adverts \| Friends	Buzzing Relay Hi there, I am in the process of wiring a set of new Daytime running lights to my Mercedes. However, I am wiring them for 2 purposes. Firstly to switch on when my interior lights switch on ( Wired to the Interior lights circuit) when I unlock the car, and secondly, to switch on when the car sidelights are switched on ( sidelight circuit). I've wired up all the relevant wires and thought everything was sweet untill I tested it out. When the interior lights illuminate the relay buzzes quite loudly for a second. Same happens when they fade off. My guess is that the relay is making the noise because it's not getting enough voltage during the on and off sequences. All wire connections/ground cable are good Does anybody know how I might be able to stop the buzzing??

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09-02-2012, 20:16	#2
Plug Registered User Join Date: Jan 2005 Posts: 9,433 Adverts \| Friends	Do the interior bulbs come on gradually and go off gradually? If so they must be an electronic resistor changing that circuits resistance, what year/car is it, I might be able to get a diagram.

09-02-2012, 20:31	#3
Aussie201 Registered User Join Date: Feb 2008 Posts: 71 Adverts \| Friends	Yes they do. It's a 00 Mercedes A 160

09-02-2012, 20:38	#4
Plug Registered User Join Date: Jan 2005 Posts: 9,433 Adverts \| Friends	Is it the front one you have it wired to and are they three bulbs in it?

09-02-2012, 20:49	#5
Plug Registered User Join Date: Jan 2005 Posts: 9,433 Adverts \| Friends	If thats the one, follow pin 4 with a grey/blue wire, look inside the light unit and there may be a little capacitor and diode. try remove that but obviously complete the circuit in the lamp unit.

09-02-2012, 20:53	#6
Aussie201 Registered User Join Date: Feb 2008 Posts: 71 Adverts \| Friends	What would the outcome be after I remove the capacitors? I'd still like to have the fade on/fade off effect when opening the doors.

09-02-2012, 21:55	#7
langdang Closed Account Join Date: Nov 2009 Posts: 3,813 Adverts \| Friends	Plug, is the power coming straight from accessory, or is coming via a control module or a relay? There is hopefully a steady 12v somewhere.

10-02-2012, 13:42	#8
Plug Registered User Join Date: Jan 2005 Posts: 9,433 Adverts \| Friends	The 12v that comes out of a control module in the instrument cluster. That is timed to turn on when the doors are opened and go out when you lock up/walk away after a set amount of time. The capacitor is on that circuit inside the lamp and if you remove it you wont have that fade effect. I don't think there is much you can do unless you make a parallel circuit, one for the lamp with capacitor and the other for the day time lights.