4 Hi Headlight Mod

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98chevy2500SS

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Damn, I didn't know Massachusetts was so **** about that type of stuff.
 

kennythewelder

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Incresing wire size does not change the voltage, it only changes the current. The OE headlight wiring is small to say the least. And then you add the lenth of the wiring, and there is a current drop, causing low out put of light at the bulb. By incresing the wire size, your increasing the amount of supply of current feeding the headlight bulb, not the volts. Like I said, electricity flows like water. Current is like volume. The bigger the wire, the more volume, or current. Maybe this video will help you to understand. More current = more flow, not more volts. A bigger wire = more current not more volts. You still have the same amount of volts, just a bigger wire for it to flow through.
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kennythewelder

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Another video about current and wire size.
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df2x4

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Kenny, one thing I don't know if you're considering is resistance in the circuit. Switching to a larger gauge of wire will reduce resistance, and therefore generally increase voltage by the time you get to whatever it is you're trying to power. @shovelbill and a few others observed nearly a full volt increase at the headlight sockets by installing HD harnesses. You're right that larger gauge wiring won't magically add voltage, but it will reduce voltage drop across the circuit. @Schurkey isn't wrong when he says that we're probably running the headlights at a higher voltage than they're generally spec'd for, although I haven't personally noticed any difference in bulb life.
 

kennythewelder

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Kenny, one thing I don't know if you're considering is resistance in the circuit. Switching to a larger gauge of wire will reduce resistance, and therefore generally increase voltage by the time you get to whatever it is you're trying to power. @shovelbill and a few others observed nearly a full volt increase at the headlight sockets by installing HD harnesses. You're right that larger gauge wiring won't magically add voltage, but it will reduce voltage drop across the circuit. @Schurkey isn't wrong when he says that we're probably running the headlights at a higher voltage than they're generally spec'd for, although I haven't personally noticed any difference in bulb life.
Yes, I agree. Thing is, the small OE wiring is a issue to start with. By using a wire just big enough to carry the amps needed to light up the headlights, then you add how long that wire is, and all the things it has to power, and there is a current drop when using a high draw object like your headlights. The whole LED headlight thing has a lot to do with this also. LEDs pull less power than regular headlights. By adding a bigger wire, you are giving a larger path for electrons to flow. The max out put of the battery is what you will have in this wire. You wont get more volts than is in the battery to start with, or than the alt will put out. thats is what the voltage regulator is for. If there is any voltage increese at all, it will only be the alt keeping up with what the draw on the battery is seeing. There is no magic increese of voltage here. It is only increesed by the amount of draw. It is no over increased because of the intalation of a bigger wire, or at least not by an significent amount. Of course this is all relevant. There is no need to supply your head lights with a 1ga wire, a 10ga wire is plenty big enough.
 

Z71Hobbs

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The other thing to consider is that modern vehicles are pushing 13 to 15 volt, with increased amperage accordingly. Unless you’re using light bulbs that are over 10-15 years old, I wouldn’t be horribly worried as the light manufactures have likely had to design accordingly for modern vehicles.
 

Ehall8702

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Digging up this thread from the grave...

Has anyone figured out how to make the 4-Hi headlight upgrade work with DTRL?

I cannot disable DTRL because of safety inspection requirements here in Mass. Some station might pass me, but I'm not driving to dozens of stations just to figure out who does it.

Have my 97&98 with quad beams, drls still work correctly. I tapped into the headlights in the main harness on the driver fender. Added a relay, close enuff for power wire to go to fuse block.
85 of relay goes to lt green
87 if relay to tan
85 of relay goes to ground
30 of relay goes to switched power with fuse in-between. I used power side of lighting fuse in fuse block. Think it's a 40a big fuse , been a while. I u pull the fuse check and see which side of where fuse goes for power and add wire to that side, that way the factory lighting is fused with its own fuse and the relay gets fused with ur add in fuse. If fuse ever pops, u still have regular functioning headlights too. I will take sum pics and try an upload them if anyone is interested tho, two sealed butt connectors , a ring terminals, and a male spade, can do it in about 10 minutes and no need to remove your grille to do it . I have leds in my pickup and everything works flawless, and regular bulbs in my gf truck cause she didn't like the LEDs.
 

slowburb

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I disabled the DRL's in my assembled in mexico '96 K1500 GMC suburban. Couldn't ever get the DRL indicator on the cluster to shut up so I just pulled the bulb. I had a painless wiring relay harness in there to replace the dinky & crusty OEM headlight wiring (but used as trigger for relays), which doubled as a 4 hi setup too. Pretty slick, and slicker with the HIR 9011 bulbs.
 

sewlow

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Have my


Have my 97&98 with quad beams, drls still work correctly. I tapped into the headlights in the main harness on the driver fender. Added a relay, close enuff for power wire to go to fuse block.
85 of relay goes to lt green
87 if relay to tan
85 of relay goes to ground
30 of relay goes to switched power with fuse in-between. I used power side of lighting fuse in fuse block. Think it's a 40a big fuse , been a while. I u pull the fuse check and see which side of where fuse goes for power and add wire to that side, that way the factory lighting is fused with its own fuse and the relay gets fused with ur add in fuse. If fuse ever pops, u still have regular functioning headlights too. I will take sum pics and try an upload them if anyone is interested tho, two sealed butt connectors , a ring terminals, and a male spade, can do it in about 10 minutes and no need to remove your grille to do it . I have leds in my pickup and everything works flawless, and regular bulbs in my gf truck cause she didn't like the LEDs.

I took the power from one of the '+' posts at the rear of the fuse block. Ring terminal. Inline fuse in a weather-proof holder.
 

slowburb

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I have the 6 hi mod on my daily driver lifted 4x4 GMT800 suburban now. It was way easier to install, just a jumper board that dropped in under the relays in the fuse block under the hood, and $20 bucks to boot. Not bad. Four HIR's and the amber cube flood/fog lights in the OEM foglight openings....that **** is like DAYLIGHT.
 
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