Classic Mustangs (Tech) Technical discussions about the Mustangs of yester-year.

Headlight Relays Questions

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Old Jan 12, 2010 | 01:43 PM
  #11  
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kalli
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i'm quite shocked at the price. but when I do such things myself then it has that trademark kalli-was-at-it look which is usually not good ...
I replaced the bulbs with H4 so it's a huge improvement already, but I want to take the load of the headlight switch as well.... might just go for the harness and be done with it .. otherwise I'll be all day at it again :-)
Old Jan 12, 2010 | 02:32 PM
  #12  
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If you put in H4's with stock wiring, get ready for a retina burn when you feed them baby's a full 14 volts. You're probably only getting 10-20% of the H4 impact otherwise.

And with all the other stuff you've done, do it yourself, don't buy the kit.
Old Jan 13, 2010 | 04:49 AM
  #13  
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tx65coupe
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Originally Posted by 67mustang302
That's the one. I had to modify the plug on their harness so it would plug into the factory headlight plug(just cut the plastic around it off with a dremel). Otherwise it was basically plug and play.
I had to do the same thing. Other than that, I really like the kit.
Old Jan 13, 2010 | 10:06 AM
  #14  
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The weak point in the stock headlight system is not the wires but the switch itself. The stock gauge wires work fine as they have since the car was new but with headlamps pulling all those amps through the weak switch, it will fail quickly. Especially these cheap replacement switches you can buy. I installed relays under the dash with the intent of isolating the stock switch from switching the high amp lights.
Old Jan 13, 2010 | 11:26 AM
  #15  
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kalli
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Originally Posted by MustangBradley
The weak point in the stock headlight system is not the wires but the switch itself. The stock gauge wires work fine as they have since the car was new but with headlamps pulling all those amps through the weak switch, it will fail quickly. Especially these cheap replacement switches you can buy. I installed relays under the dash with the intent of isolating the stock switch from switching the high amp lights.
that will already help the switch itself, but all those connectors are not doing you a favour. I really believe the way to go forward is straight to the lamps without any connectors in place for the powered circuit
Old Jan 13, 2010 | 12:18 PM
  #16  
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4reboy
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Originally Posted by MustangBradley
The weak point in the stock headlight system is not the wires but the switch itself. The stock gauge wires work fine as they have since the car was new but with headlamps pulling all those amps through the weak switch, it will fail quickly. Especially these cheap replacement switches you can buy. I installed relays under the dash with the intent of isolating the stock switch from switching the high amp lights.
When you add relays in the fashion I as well as others have done the only thing the switch is for is switching on the relays to power the headlights or hi-beams. If you make a new headlight harness then that one just plugs into your old harness, from there it goes to the relays where it boosts up the power and then to the headlights. Nothing needs to be done to the switch because it is still acting on the stock harness, just before the relays. I don't see how adding relays to the switch itself, or changing the switch in any way, will help you. It is much easier to just put in a 12 AWG harness, either bought from somewhere or made at home like I did.
Old Jan 13, 2010 | 12:37 PM
  #17  
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kalli
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what he did (i guess) was to use the otiginal harness and from the switch went into the relay and fromm there out to the lights. this gets all the load of the switch, but not off the harness and connectoes in firewall.
Old Jan 13, 2010 | 06:41 PM
  #18  
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I was looking for a simple solution to the problem I had which was headlight switches that lasted a short time. My headlight switch now is used to switch the relays so it is exposed to only a few milliamps. Granted, I could have run all new wires or mounted the relays close to the headlamps but I'll tackle that problem when and if it arises.
Yes I added a few connectors in the mix but they are shrink wrap protected and inside the car so I expect no problems.
Old Jan 15, 2010 | 03:38 PM
  #19  
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nba1341
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So i just took out both headlights and see that on the driverside headlight pigtail there are 2 wires going into the backside versus 1 for the passenger


Im guessing the wires from the headlight switch go into driver side then wires split out and go to the passenger side. Installing the relays on the passenger side and tapping into that pigtail will still energize the relays correct?
Old Jan 15, 2010 | 06:02 PM
  #20  
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chris66dad
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I had to replace the harness for the headlights after I installed the relays. The passenger side light was dimmer than the drivers side. I used 12 gauge wire for the new harness and now both lights are equal and brighter than before. I also bought new connectors for the back of the lights that were made for the higher temps.



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