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Headlight wiring for mk2 to mk2.5 upgrade

Posted: Thu Aug 25, 2016 4:02 pm
by Crazyassdrummerboy
Hey there first post here!

I was just wondering whether anyone has successfully managed to have their high beams AND low beams on at the same time after a NB1 to NB2 front end conversion. Most threads just use a simple H4 to HB3/HB4 adapter which means the low and high just alternate.

I came up with this wiring diagram but not 100% sure if it would work correctly.

NBconversionwiringV3.jpg

Any of you guys on here able to confirm that this would work? Or do I need to add/change anything?

Cheers!

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Thu Aug 25, 2016 10:20 pm
by Locutus
You've shorted the low and high beam inputs together so you can't have one on without the other?

Image

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Fri Aug 26, 2016 12:28 am
by Crazyassdrummerboy
I figured by having the high input run to the low relay it would always run all 4 lights, but when lows are on the highs remain off until switch activated

What I don't get about the diagram you posted is the 2 power inputs to the high beam bulbs. Would that work with a HB4 bulb?

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Fri Aug 26, 2016 3:17 pm
by Locutus
You've joined them so they will both turn on when either is on. Electricity flows both ways along a conductor.

In my diagram, just ignore the bits you don't need.

Or in your diagram, rather than joining terminals 85 together, join terminal 87 of the high beam relay to terminal 85 of the low beam relay.

Or get the work done by an auto electrician so your car doesn't catch on fire.

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Fri Aug 26, 2016 3:36 pm
by Crazyassdrummerboy
So the only change I needed to make was have 2 lines out from the High beam relay 87 port

NBconversionwiringV3.jpg

Auto electricians want in excess of $150 for this and I like the ability to make my own components

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Fri Aug 26, 2016 3:57 pm
by Magpie
I would suggest a diode on each of the "green" wires (from 85 and 87), however may not be practical depending on the amps of the circuit.

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Fri Aug 26, 2016 5:43 pm
by Crazyassdrummerboy
In an ideal world it would have been simple like this for each side harness

NBconversionwiringV1.jpg

but the voltage drop would affect the output too much

Re: Headlight wiring for mk2 to mk2.5 upgrade

Posted: Sat Aug 27, 2016 12:56 pm
by Locutus
Crazyassdrummerboy wrote:NBconversionwiringV3.jpg

This should work just fine.