# Wiring plow lights hi/low beam with relays



## Charlie'sChaps (Nov 24, 2012)

Hi,

I am in the process of wiring plow lights with relays. The kit I got with my plow is the old style DPDT switch you are suppose to tap off the floor switch for hi/low beams. Needless to say, I don't want to go that route.

This is the diagram I want to follow but have a question.

I see that you tap off the existing bulb connector and wire the relays and the plow lights. Now my question is where do you attach the leads from 87A that go back to the vehicle headlights (high/low) Do these run back to the lights downstream from where I made the initial tap?

Any suggestions would be great.

Thanks.


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## dieselss (Jan 3, 2008)

the leads ftom 87a goto the light themselfs. your gunna have to take off the factory headlight connector, and install another one,
and as far as i see it, you have 2 options.
1) use only the 4 relays for both lights
2) use 8 relays, 4 for each side.
and just fyi theres some places tha sell the male end of the headlight connector, depending which ones you have


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## jasonv (Nov 2, 2012)

Charlie'sChaps;1527692 said:


> Hi,
> 
> I am in the process of wiring plow lights with relays. The kit I got with my plow is the old style DPDT switch you are suppose to tap off the floor switch for hi/low beams. Needless to say, I don't want to go that route.
> 
> ...


Your diagram seems a bit heavy on the relays, light on the actual necessities.

First off, your truck already has relays for the headlights, both high and low beams. There is no sense in duplicating them. In other words, your two SPST relays are redundant.

What I would do, is determine how many circuits the truck has for running the headlights. Some vehicles run only a SINGLE circuit to power BOTH low beams, and a second SINGLE circuit to power BOTH high beams. Other vehicles use four separate circuits to run left, right, low and high beams. You can find the number of circuits by checking the number of headlight relays your vehicle has, and how many outputs each relay has. If it has just ONE SPDT relay, it is a TWO circuit system, one for high, and one for low. If it has a DPDT relay, or two SPDT relays, it is a FOUR circuit system.

In a TWO circuit system, you need a total of TWO SPDT relays. In a FOUR circuit system, you need FOUR SPDT relays.

Wire it like this;
Find a SWITCHED POSITIVE source, i.e., one that is ON or OFF with the ignition switch. This is important because you don't want to drain the battery by leaving the system on "plow lights". Wire your truck/plow SPST switch into the coils, other side of the coils to ground. SOURCE wire to common connector on the relays, NORMALLY CONNECTED (NC) to TRUCK lights, NORMALLY OPEN (NO) to PLOW lights.

So what this will do, is switch the switch the power from truck to plow lights when the switch is turned ON.

Now if you want to get FANCY with this, get yourself a couple of DIODES. They each need to individually be able to withstand the voltage and current required to power the RELAYS. Wire the positive sides of the two diodes each into a source HIGH, and a source LOW (it doesn't matter if your truck is a 2 circuit or a 4 circuit, just pick ONE low and ONE high circuit). Connect the negative sides together and use THAT as the power source for your truck/plow switch. Now the relays will be powered any time the lights are turned ON AND the switch is turned to the "plow" side.

A diode is basically a one-way-valve for electrons. Wired like this, they basically form an "OR" circuit, without letting the two circuits bleed into each other. It provides power to the "system" if your low beams are on **OR** if your high beams are on.

Your logic equation would be like this;

(HIGH OR LOW) AND (PLOW) = POWER_RELAYS


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## 2COR517 (Oct 23, 2008)

Of all the projects I should have taken pics of........

Jason,

How do you know his truck already has relays for the headlights?


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## jasonv (Nov 2, 2012)

2COR517;1527970 said:


> Of all the projects I should have taken pics of........
> 
> Jason,
> 
> How do you know his truck already has relays for the headlights?


Simple: because it takes a BIG FRIKKING CLICKER to handle 8.3 amps (2x60 watt bulbs = 120 watts, divided by 14.5 volts = 8.3 amps) reliably over long term use. Dashboard level switches are universally LOW current switches. Relays are under the hood to run things like headlights. The low current switch will activate the high current relay.

Alternatively, maybe he drives a truck made in the 50's that HAS a BIG FRIKKING CLICKER of a headlight switch.

Either way, there is no reason to add another relay.


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## 2COR517 (Oct 23, 2008)

Hey, thanks for making it really clear to the rest of us just how much you know about vehicle electrics....saved me some work.


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## Holland (Aug 18, 2010)

2COR517;1527991 said:


> Hey, thanks for making it really clear to the rest of us just how much you know about vehicle electrics....saved me some work.


Duh, all you need is scotch locks and electrical tape.


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## dieselss (Jan 3, 2008)

Why even bother with the tape. Scotch locks are the only way to go


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## 2COR517 (Oct 23, 2008)

Holland;1528039 said:


> Duh, all you need is scotch locks OR electrical tape.


One or the other is all you need. One or the other


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## Holland (Aug 18, 2010)

dieselss;1528045 said:


> Why even bother with the tape. Scotch locks are the only way to go





2COR517;1528049 said:


> One or the other is all you need. One or the other


well, "technically" you could do it that way.. but its best to do it the PROSELFINAL way


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## dieselss (Jan 3, 2008)

Yea. Scotch locks. Ok I can't even say that with any honesty 
There's no technically. It shouldn't be done that way !!


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## Holland (Aug 18, 2010)

dieselss;1528089 said:


> Yea. Scotch locks. Ok I can't even say that with any honesty
> There's no technically. It shouldn't be done that way !!


Hey now! Theres a place for them... the trash! Thumbs Up


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## basher (Nov 13, 2004)

Charlie'sChaps;1527692 said:


> Hi,
> 
> I am in the process of wiring plow lights with relays. The kit I got with my plow is the old style DPDT switch you are suppose to tap off the floor switch for hi/low beams. Needless to say, I don't want to go that route.
> 
> ...


If you are going to build your own harness buy a set of one of the manufacturer's headlight adapters for your truck so you can use the headlight plugs instead of cutting the harness. It will also assure you get the right wires.


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## Charlie'sChaps (Nov 24, 2012)

It's a 07 F150. I want to use the headlights as well as the plow lights and switch between them.

I like the idea of using some headlight adapters.

The wiring that came with my plow lights is seriously lacking. I do not like it at all. I don't want to go from the trailer plug, seems foolish to me.

I will have to look around a little more. I am mechanically inclined, just not in advanced electronics  And yes, multiple relays etc. to me is advanced electronics LOL.

Thanks guys.


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## B&B (Nov 4, 2006)

jasonv;1527911 said:


> First off, your truck already has relays for the headlights, both high and low beams.


 Not on an 07 F150, only one headlamp relay on those. And it isn't under the hood.



jasonv;1527982 said:


> Simple: because it takes a BIG FRIKKING CLICKER to handle 8.3 amps (2x60 watt bulbs = 120 watts, divided by 14.5 volts = 8.3 amps) reliably over long term use. Dashboard level switches are universally LOW current switches. Relays are under the hood to run things like headlights. The low current switch will activate the high current relay.


Again, not on an 07 F150. There is no low beam relay. Lows are powered directly through the big frikking clicker...as you gallantly put it. .


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## Charlie'sChaps (Nov 24, 2012)

B&B;1528327 said:


> Not on an 07 F150, only one headlamp relay on those. And it isn't under the hood.
> 
> Again, not on an 07 F150. There is no low beam relay. Lows are powered directly through the big frikking clicker...as you gallantly put it. .


OK. So if I may bother, what is the best way to wire these plow lights in conjunction with the existing lights? I could just tap into the fog lights to get low beam plow lights but I want to get the deluxe package. 

Thanks.

Charlie.


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## dieselss (Jan 3, 2008)

Just get 2 flashlights ans duct tape them to the plow. There done,,and no wiring involved. Bahaha. Lol


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## Charlie'sChaps (Nov 24, 2012)

dieselss;1528384 said:


> Just get 2 flashlights ans duct tape them to the plow. There done,,and no wiring involved. Bahaha. Lol


I'm Canadian, I will use hockey tape!


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## dieselss (Jan 3, 2008)

Ok sorry for the mix up. Eh! Lol


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## dieselss (Jan 3, 2008)

Do you want the easy way to do this ?? Switch, relay, wiring spst switch.(2 or 3 pin switch). Get hot wire from an ign source, to switch. Out to relay...one lead off battery, and gnd. Last lead out to the plow lights. Nice and easyinstall, no heavy wires in cab,,,and the plus of only plowing with your headlights on and nothing else


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## Charlie'sChaps (Nov 24, 2012)

dieselss;1528441 said:


> Do you want the easy way to do this ?? Switch, relay, wiring spst switch.(2 or 3 pin switch). Get hot wire from an ign source, to switch. Out to relay...one lead off battery, and gnd. Last lead out to the plow lights. Nice and easyinstall, no heavy wires in cab,,,and the plus of only plowing with your headlights on and nothing else


Ya, that will work. Can I take it one step further and include plow hi-beams with an additional relay and 3 position switch?


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## dieselss (Jan 3, 2008)

Yes you can,,,same principle...but if I can throw my 2$ in. Just wire it up on high beam from the start,,and adjust your lights as necessary. May I ask what kinda lights you have? I might even have more helpful tips for ya


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## Charlie'sChaps (Nov 24, 2012)

dieselss;1528476 said:


> Yes you can,,,same principle...but if I can throw my 2$ in. Just wire it up on high beam from the start,,and adjust your lights as necessary. May I ask what kinda lights you have? I might even have more helpful tips for ya


They are Grote sealed unit hi/low beam with turn signals. 
per-lux 6242 5 wires coming off of them. Red, green, blue, yellow, and white.


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## dieselss (Jan 3, 2008)

Oh ok gotcha I really got nothing for those then. Just the old westerns


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## Charlie'sChaps (Nov 24, 2012)

That's fine. You have been a great help, thanks.

Now to the switch, is an on off on a SPDT? bottom lead for low, centre for off, and top for hi?


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## dieselss (Jan 3, 2008)

Yea. Just make sure you don't get a mon or mom switch as you have to hold the switch in the position you want


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## Charlie'sChaps (Nov 24, 2012)

Excellent, thank you for your time sir.


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## dieselss (Jan 3, 2008)

No bother at all. Keep us informed tho. Maybe even pics


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