# Simultaneous High/Low beam headlights



## Ed257 (Jan 27, 2003)

Can anyone help me? I am looking for an inexpensive way to have the low beam lights stay on when high beams are on.
The truck is an 02Chev 2500HD with DRL's

It also has a Western snow plow harness installed.

Thanks Ed


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## Arc Burn (Oct 21, 2002)

Summit Racing has a kit,under $25 i believe,i know it worked on the 88'-98' Chevys.


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## JohnnyU (Nov 21, 2002)

How would that kit work when the plow is on, can or do both filaments in the sealed beam light of the plow be lit? I have been wondering about this kit's compatability with a snowplow for sometime now, but never wanted to find out the hard way...


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## wyldman (Jan 18, 2001)

It would work with the single filament bulbs,but they would burn out very quickly if you do.

You could build a setup,that would cancel that feature when the plow is connected.

The "kit" that most places sell is just a relay that turns the low beams on when it see the high beams activated,and takes the extra load off the headlamp switch.You can make one yourself very easily,with a couple of relays and some better wire.

I can post a wiring diagram if anyone is interested,and i'll show you how to make it work with the plow lamps.


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## Arc Burn (Oct 21, 2002)

Post away Chris!i myself would like to see how they do that,thanks


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## wyldman (Jan 18, 2001)

I will be back in the office tommorow sometime,and i'll sketch one out and scan it for you guys.


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## Ed257 (Jan 27, 2003)

*Please do*

Chris, you sound like the one I need to hear from. I have been experimenting with the lights and relays but havn't had much luck. I will wait for your diagram.
Thanks a Lot
Ed


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## wyldman (Jan 18, 2001)

Most of the aftermarket kits are NOT compatible with the auto switchinh headlamps on the newer plows.The diagram I am posting here is not either,if you use the diode.I will post another for the plow headlamp setups.

Here is a basic dual relay setup which will serve four functions.First off,it will take the load off your headlamp switch,so it should never burn out,like a lot of them do.Second,it will supply full battery voltage to the headlamps by eliminating the voltage drop across the headlamp switch,which makes them MUCH brighter.Third,with the diode installed between the two relays,you will keep the low beams on while the high beams are on.Fourth,if you have factory fog lamps,they most likely go off when you switch the high beams on,this setup will most likely keep them on as well,depending on how the factory wired them.

Only use the diode if you have separate bulbs for high and low beam.It will work for dual filament bulbs,but having both filaments on in one bulb will cook it pretty quick and possibly melt your headlamp housing.Consider yourself forewarned.

If you just want brighter headlamps,or don't have separate bulbs for high and low beam you can still use the relays to help the headlamp switch and make them brighter.Just eliminate the diode between the two relays.

All battery and ground wiring should be min 10 GA with a fusible link or ciruit breaker rated at 30 amps.The wiring from the relay to the headlamps should be 14 GA min.All other wiring is 16 or 18 GA.Use a good quality Bosch relay,thats what the numbers on the diagram correspond to.If using a different type just hold the relay in the same way as the diagram,and you will see which pins are which.Potter and Brumfield also make excellent relays,just more expensive and harder to get.The diode can be had at Radio Shack or any electronics store,just a small one (500 ma) is all you need.Solder and heatshrink all connections,no crimp connectors,as they will get hot and cause a voltage drop.

I will post the setup for a plow later,gotta grab a cat nap,been up for almost 48 hrs.So please excuse me if I missed anything.


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## wyldman (Jan 18, 2001)

Duh ... would have help if I attached the diagram


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## wyldman (Jan 18, 2001)

Forgot about the DRL's.On the newer GM's I think they use a separate bulb for the DRL,so it won't make a difference,it will still work.

If your truck uses the high beams at reduced power for the DRL,try it,it still may work,if the reduced voltage is still enough to trigger the relay.If not,then you will have to unplug the DRL module,and lose the DRL,or you can run a power wire from the IGN swtich,hot in the run position,to trigger the low beam relay when the key is on.You will need to install a diode inline there as well,so if you turn the headlamps on,without the truck running,it won't feed back through the IGN circuit.The arrow or line on the diode will go towards the relay.Just remeber not to leave the key in the run position without the truck running,or your headlamps will stay on,and kill the battery.Use the ACC positiion and they won't come on.If you want to get real fancy,you could tie into the oil pressure sender so they only come on with the truck actually running.If you want to go this far,e-mail me and I'll do you up something to show you how to do it.


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## wyldman (Jan 18, 2001)

Here is the mod to make it work with a plow setup.Diagram shows pins and wire colors for the western style,buit you can make it work on pretty much any plow.Just add in the relay,and connect the wires as shown.The relay can be a micro relay as it doen't really carry any power,but it must be a SPDT relay,just like the plow relays.The new headlamps realys are just regular SPST.To distinguish the two,SPST has two output pins that are common,both marked 87.SPDT relays have two output pins that are switched,marked 87 and 87A.

I didn't do a diagram for it but you will need to take the outputs for high and low beam,from your new relays (pins 87),and connect them to the corresponding plow relays (pins 30).These pins will be empty,as you remove them as described in the diagram.Make good quality jumper wires,use 14 GA wire.It also wouldn't hurt to upgrade the wiring from your plow relay outputs (pin 87A) to the truck headlamps,use 14 GA as well.


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## wyldman (Jan 18, 2001)

Forgot the attachment again :realmad:


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