Lets go overkill on the old headlight loom shall we....

[deanpompey 0]

Right, i decided today to build myself an uprated headlight loom, and am happy enough with 90% of it, just having a bit of bother getting my head round some things...

 

pin numbers/uses - have seen diagrams in various places giving the pins and what they should be, but have seen some conflicting ones....am i right in thinking the following:

 

Pin 30 - Battery live

Pin 85 - Earth

Pin 86 - input

Pin 87 - output

 

Also, am i right in thinking the H4 bulb uses the first filament for sidelights, and second/both for dipped beam, and the inner H3 bulbs power main beam? im assuming that i lose the dipped beam when the main beam is on, can i wire it up so as they both work at same time?

 

i am also going to relay my fogs, should i use one relay for both of them, or one relay per fog?

and can i relay the sidelights too?

 

as i see it i need the following

 

2 relays dipped beam

2 relays main beam

2 relays fogs

 

???2 relays sidelights???

 

 

Sorry for all the Questions, have made looms for mk2 golfs before but only ever 2 relay looms for dipped beam! this is bit more challenging for me!

 

Cheers

[quicky1980 0]

dont you just need 3 relays, one for the main, low and fogs? I wouldn't bother with the fogs tbh.

[krnau 0]

what I did was to use two relays per each headlight. It is, in the first headlight, one relay for the low beam, and another one for high beam.

 

Headlight connector has 4 pins. One is earth, one for positioning, one for low beam, one for high beam. you really have to use a polymeter in order to guess which pin is used for low and which one for high beam, and then find the earth pin.

 

Then, if you upload a picture of the relays you have bought, I will help you about the electrical connections.

 

 

and same for fogs: one relay per fog.

 

 

so if you want to uprate everything, you need 6xrelays (and 2+ for positioning lights if you want :lol: )

[deanpompey 0]

One relay per beam means that if a relay dies or a fuse goes, you lose both lights, not good if you happen to be hooning down a country road at the time! :gag:

 

im cool with the headlight plug wiring, its more what i can relay thats proving difficult.

 

 

The relays are OE Hella 12v 40A Relays (number 18 as used in mk3/4 golfs, audi a3/4 etc) part number is: 4RA003510-58

 

i think i prob will relay the sidelights (positioning lights as you call them :) ), simply because i can, and everything else will be! :shrug:

 

the whole side/dipped thing has got me wondering though, will i have to splice into the wires behind the plugs to run them off seperate relays or can i still just use one relay?

 

anyone got diagrams for me to ponder??

 

cheers

[krnau 0]

One relay per beam means that if a relay dies or a fuse goes, you lose both lights, not good if you happen to be hooning down a country road at the time! :gag:

 

im cool with the headlight plug wiring, its more what i can relay thats proving difficult.

 

 

The relays are OE Hella 12v 40A Relays (number 18 as used in most 93+ VW's) part number is:

 

i think i prob will relay the sidelights (positioning lights as you call them :) ), simply because i can, and everything else will be! :shrug:

 

the whole side/dipped thing has got me wondering though, will i have to splice into the wires behind the plugs to run them off seperate relays or can i still just use one relay?

 

anyone got diagrams for me to ponder??

 

cheers

 

 

no. I meant, relays (and fuses):

 

1 x d/s low beam

1 x d/s high beam

1 x d/s fog

 

1 x p/s low beam

1 x p/s high beam

1 x p/s fog

 

 

so in the case that one fuse/relay dead, you still have the other ones. i.e. passenger side low beam relay/fuse goes wrong, you still have driver's side one :)

[deanpompey 0]

yeah i understand that bit. the one relay etc comment was for quicky.

 

but a H4 connector has 3 pins, not 4, so im guessing its the current passed through it that dictates 1st/second filament? so would this still be applicable to the relay situation, ie:

 

1 x d/s low beam AND sidelight

1 x d/s high beam

1 x d/s fog

 

1 x p/s low beam AND sidelight

1 x p/s high beam

1 x p/s fog

 

OR

 

1 x d/s Sidelight

1 x d/s low beam

1 x d/s high beam

1 x d/s fog

 

1 x p/s sidelight

1 x p/s low beam

1 x p/s high beam

1 x p/s fog

 

??

[quicky1980 0]

One relay per beam means that if a relay dies or a fuse goes, you lose both lights, not good if you happen to be hooning down a country road at the time! :gag:

 

you are correct, but this is unlikely. In fact if you do it correctly it will be as reliable as the fuse and relay setup that vw do which Im pretty sure is one relay to control both high and low beams.

 

having a relay up front is used to shorten the distance the current has to travel through wiring from the battery to the headlamps. but could be talking :censored: as I am not an electrical engineer

 

entirely your choice, just trying to save you some work and money

[krnau 0]

yeah i understand that bit. the one relay etc comment was for quicky.

 

but a H4 connector has 3 pins, not 4, [...]

 

 

well really it's done internally in the headlight, but you will put the relays out of it so why worry about it? Sorry, I don't understand what you mean :?

[deanpompey 0]

so the pin on headlight plug that has the two (side/dipped) beam signals can just be joined and connected direct to the relay signal pin as per standard headlight plug and one relay plug can earth, or do i take both to diff pins on relay and earth from headlight plug?

 

im finding it hard to explain what i mean :?

[krnau 0]

so the pin on headlight plug that has the two (side/dipped) beam signals can just be joined and connected direct to the relay signal pin as per standard headlight plug and one relay plug can earth, or do i take both to diff pins on relay and earth from headlight plug?

 

im finding it hard to explain what i mean :?

 

there are 4 pins in each headlight plug.

 

passenger side:

a) positioning light (well, the first position of the headlight switch) -> does not need to be relayed

b) low beam -> goes to relay number 1

c) high beam -> goes to relay number 2

d) earth (common for all the other 3 pins).

 

 

driver side:

a) positioning light (well, the first position of the headlight switch) -> does not need to be relayed

b) low beam -> goes to relay number 3

c) high beam -> goes to relay number 4

d) earth (common for all the other 3 pins).

 

 

if that's not clear, I'll upload a quick diagram tmrw :)

[deanpompey 0]

kinda clear, but a diagram would be better! :)

 

i was gonna relay the positioning lights anyways as mine are crap. can that not be done then?

 

i was assuming that mk2 golf headlight plugs are same as rado, in which case a and b would go to the same pin on the plug. ill find and upload pics tomo to show you what i mean, if your diagram doesnt put me on right track :lol:

[krnau 0]

kinda clear, but a diagram would be better! :)

 

i was gonna relay the positioning lights anyways as mine are crap. can that not be done then?

 

i was assuming that mk2 golf headlight plugs are same as rado, in which case a and b would go to the same pin on the plug. ill find and upload pics tomo to show you what i mean, if your diagram doesnt put me on right track :lol:

well as you have understood the thing about the 4 relays, then the diagram isn't needed really, because it was only to you this to you.

 

What you need now is to guess which pins are for hi/lo/pos/gnd. I had it written down on a piece of crappy paper but it was 3 years ago and the paper may have desintegrated :lol:

[deanpompey 0]

yeah that bit is easy enough mate cheers