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ok guys i got a set of H4 healights in my datto they came with the headlights buckets so i figured i would run them but i was checking fuses tonight (looooong story) and the ones for the headlights were hot enough to burn my finger to the point it blistered are the headlights the only thing on theses fuses? do i need to run a higher amprage fuse to use theses lights? any info would be great thanks

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wll you have 2 choises. run a bigger fuse and risk burning down your car, OR...... an aftermarket or self made 30 amp relayed harness. i have run several myself with good luck. i am begining to think the factory HL relays aren't good enough for the system. my HL fuse on my truck melted the block. too much power running through.


heres the parts list that i have for a nice relay setup.

2 or 4 30 BOSCH relays (the ones with the eye at the top for mounting. you can run 2 relays, one low one high as they ahve 2 outputs, or 1 for each headlight but that requires more wiring)


a couple inline fuses OR a seperate X-gang fuse block. ( i use a 6 gang as i like to install fog lights. )


12 guage wire. 20 ft should work


new or used HL connectors (to retain a redundancy system. always good to have if a relay dies)


some spade connectors both male and female




heatshrink tubing


30 amp fuses


and electrical tape


the most expencive part is the relays which usually run between $7-$15 depending on what ones you get. the Blazer ones work good as i have used them before. another alternative to making your own harness, like if you suck at electrical, would be to BUY a premade H4 harness but then you dont get the inner lights relayed. its really up to you how you would like to go about it. it takes about an hour or so to make the relay harness and it can be made off the car BUT its almost easier, in my experience, to make it on the car. that way you can hide the wires through the core support and take the hassle out of having to figure out how to run the wireing after its done. the down side being you wont have any covering for them.



if you want i will make a writeup on mine when i go to do it. kindof a how to for the group??? hell i think i have enough rocco HL connectors lying around, if i have enough parts hidden around i might just do my truck tomorrow and post a how to.


just so you know i have done this several times. my 77 power wagon, my 71 dart, a freinds 89 crown victoria, and a person i knew a while ago had this setup, all wired by me with plans off the internet. its a reliable system adn the only deviation from the plans was my redundency plan. use the original wiring to switch the relays but dont remove teh plugs. hence where the male spade connectors come into play.

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hmm good info i was thinking about running relays to power them i need to run them to power my foglights so i should just rrun another for my headlights sounds to me like ill need 3 relays in all (2 for headlights 1 high 1 low and one for fogs) wiring isnt to hard i can make a harness i just wired up my fan controler im my car today i think i can do this lol thanks for the info

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sounds bout right. and a multi gang aux fuse block would be good for keeping the wiring neat and tidy. the foglights you can get a premade harness which would save alot of time. i KNOW pepboys carries them as thats where i have bought them before. if you do go that route and buy the fog harness make sure to get teh PILOT or Piaa harness. all self contained with a white cable covering, bug style on off switch and relay. they work GREAT!!!!!! and the lengths are pretty dead on for most cars.

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i found a wiring diagram online but i have a question do i need to take the signal wire (what used to suply power) from both headlights to the relay? or just one


i was also looking at my fuses in conjuntion with the headlights 30 amp bulbs running threw a 10 amp fuse :eek::eek: no wonder them bitches were hot:lol:

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napa sucks for harnesses. any place that sells "ricer" parts should have em. as for the signal to trip the relays all you would need is from one. thats all i have ever run. and you can use the closest of the original HL connectors to do that. what i do is insert one spade connector, wired to the proper relay prong, into the slot for the low bean and the same for the high. that will be enough to trip the relays. that will take a HUGE load off the already stresed harness. and it should make your lights a whole lot brighter as well. even 35watt incandesents like i still have on my truck....... well 1 halogen 3 incandesents.

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