How do I install relay harness if battery is in the trunk?

davealvarez2000 · 01-13-2012, 01:59 PM

hey guys,
thanks for the suggestions on fixing my HID kit. I understand I need to get a relay harness in order for my HID kit to work because there isn't enough voltage to power them on. I know i need a relay for the low beams, would I need a second relay for the foglights too? Also, since our batteries are in the trunk, how do I connect the relay power and ground from the hood (the positive and ground connections are short length from the relay since most batteries are in the front). Thanks!

Chris@codemybimmer · 01-13-2012, 02:50 PM

under the hood there is a red cap that as a + on it. thats the positive connector that links to your battery. ground is anywhere else.

Chris@codemybimmer · 01-13-2012, 02:51 PM

http://i45.tinypic.com/2qmnnzn.jpg
looks like that, it son the passenger side

e90n52b30 · 01-13-2012, 05:04 PM

You'll want to put a 20-25 amp fuse on that wire as well.

You can use the same relay for 2 ballasts. I believe the relays are 25 amp. Not sure, I guess it depends which one you got.

I would use 2 relays if you want to be able to control the fogs separately from the headlights.

01-13-2012, 01:59 PM	#1
davealvarez2000 New Member 4 Rep 16 Posts Drives: 2007 328 XI Join Date: Jan 2011 Location: Pennsylvania iTrader: (0)	How do I install relay harness if battery is in the trunk? hey guys, thanks for the suggestions on fixing my HID kit. I understand I need to get a relay harness in order for my HID kit to work because there isn't enough voltage to power them on. I know i need a relay for the low beams, would I need a second relay for the foglights too? Also, since our batteries are in the trunk, how do I connect the relay power and ground from the hood (the positive and ground connections are short length from the relay since most batteries are in the front). Thanks!
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01-13-2012, 02:50 PM	#2
Chris@codemybimmer 172 Rep 1,397 Posts Drives: AW F30 328i Xdrive Join Date: Jan 2012 Location: Toronto iTrader: (1)	under the hood there is a red cap that as a + on it. thats the positive connector that links to your battery. ground is anywhere else.
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01-13-2012, 02:51 PM	#3
Chris@codemybimmer 172 Rep 1,397 Posts Drives: AW F30 328i Xdrive Join Date: Jan 2012 Location: Toronto iTrader: (1)	http://i45.tinypic.com/2qmnnzn.jpg looks like that, it son the passenger side
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01-13-2012, 05:04 PM	#4
e90n52b30 Banned 3 Rep 119 Posts Drives: '06 AW E90 330xi Join Date: Jan 2012 Location: NJ iTrader: (0)	You'll want to put a 20-25 amp fuse on that wire as well. You can use the same relay for 2 ballasts. I believe the relays are 25 amp. Not sure, I guess it depends which one you got. I would use 2 relays if you want to be able to control the fogs separately from the headlights. Last edited by e90n52b30; 01-13-2012 at 05:25 PM..
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