Wiring a relay into fog light switch

mr-charisma · Post by **mr-charisma** » Wed Jan 23, 2008 11:58 pm

I've just bought a new fog light switch from the wreckers ($20), took it apart cleaned it a bit & put it back together

I've searched the forums & found a few posts about wiring in a relay, but it's doing my head in ..

The most helpful post has been this one;
http://www.ftoaustralia.com/modules.php ... ght+switch

But what I really need is a straight forward diagram or instructions that tells me which wires I need to plug into which pins of the relay.

From what this guide tells me, I need to connect the two Red wires to 30 & 87 on the relay
and connect the two middle wires (green/white & Black/Yellow) to 85 & 86 on the relay.

But it doesn't say which order it needs to be in. Does it matter?

Also, does anything need to be connected to 87a on the relay?

This is a diagram of the relay. (sorry for mspaint dodgyness)

Here is how I imagine that it needs to be wired up, can anyone confirm if this is right?

mr-charisma · Post by **mr-charisma** » Thu Jan 24, 2008 12:09 am

oh & this is a diagram of the connector plug for the switch

DaveO · Post by **DaveO** » Thu Jan 24, 2008 8:14 am

G'day mr-charisma
If you have the red wires coming out of the switch to the fog lights at the moment then the red goes from the switch to 85 and 86 goes to earth. That will energize the relay or pull the contactors. You provide power from the battery to 30. 87a goes to the fog lights, that will be the other half of that red wire.
If you connect to 87 instead of 87a then the lights will be on by default. You don't want that.
Hope that helps
DaveO

mr-charisma · Post by **mr-charisma** » Thu Jan 24, 2008 6:06 pm

lol, just confusing myself even more now..

So now I need to know which wires are for what .. I think i've tracked down that;

Green / White = + constant power
Black / Yellow = Earth / Ground wire
Red = Fog lights??
Green / Orange = parkers??
Green / Black = parkers??

What is the Red/Black wire for? just for completing the circuit with the red wire for the fogs?

Let me take another stab at this

30 = Green / White (Constant power from battery?)
85 = Red wire (Fog light +)
86 = Black/Yellow (Earth)
87 = Red/black???
87a = Red (Fog light switch side)

DaveO · Post by **DaveO** » Thu Jan 24, 2008 7:30 pm

mr-charisma wrote:lol, just confusing myself even more now..

So now I need to know which wires are for what .. I think i've tracked down that;

Green / White = + constant power
Black / Yellow = Earth / Ground wire
Red = Fog lights??
Green / Orange = parkers??
Green / Black = parkers??

What is the Red/Black wire for? just for completing the circuit with the red wire for the fogs?

Let me take another stab at this

30 = Green / White (Constant power from battery?)
85 = Red wire (Fog light +)
86 = Black/Yellow (Earth)
87 = Red/black???
87a = Red (Fog light switch side)

If your only wiring in a relay then the red wire is the only one you need to interupt.
This is of course assuming that by putting in the new fog light switch you have everything working properly that is your parkers and fog lights work as expected.
The relay only protects the switches and there wiring from overloading it allso insures that your getting good clean voltage directly to the lights.
Hope this helps
DaveO

mr-charisma · Post by **mr-charisma** » Thu Jan 24, 2008 7:45 pm

I'm replacing the burned out switch & plug & adding a relay so that it doesn't burn out again in the future.

So the replacement plug I have got from the wreckers has been snipped & has a bit of length to play with on the wires..

I guess have to join some wires as they already are & plug others into the relay (I assume that the wires for the parkers can just be joined & won't need to be wired in to the relay)

DaveO · Post by **DaveO** » Fri Jan 25, 2008 7:45 am

mr-charisma wrote:I'm replacing the burned out switch & plug & adding a relay so that it doesn't burn out again in the future.

So the replacement plug I have got from the wreckers has been snipped & has a bit of length to play with on the wires..

I guess have to join some wires as they already are & plug others into the relay (I assume that the wires for the parkers can just be joined & won't need to be wired in to the relay)

What I suggest is to wire the plug so that it all works as it should with parkers and fog lights going off and on as designed.
When your happy with that then install the relay by interupting the red wire or what ever color it is that goes to the fog lights.
Leave the parker circut as is, they don't need a relay. That way your not fault finding two possible circuts.

DaveO