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Big time Electrical Relay question(4 light headlights)
Ok..tricky stuff here so this is for Electrical gurus..no guesses!
ALL 4 lights are single Filament.This means that all lights have 2 wires only and are of the same wattage.( have no clue why I could not get a 3 wire bulb..would have been easier).
So I need to know If I can take TWO relays and operate the lights to get HI and LO.
I would like to use one relay for LO and the other for HI.
My Biggest question is can I gang 87 and 87A together on ONE relay (which would be the LO Relay)so that the LO's will be on at ALL times and then the other Relay used to activate the HI only set of lights.
The Coil side of the Relay would be connected to the Stock connector on the FC light system so that the switch can activate the relays for LO and HI.
Last edited by misterstyx69; Jun 22, 2016 at 01:35 AM.
The 5 wire relay just might work for this actually...because 87 would be on when relay is activated and 87a when relay is in "off" position (or vice versa - I can't remember)....hmmmmmmmmm...now you have me thinking too.
The dimmer relay has two wires coming off of it that runs to the headlights, one (R/B) for low beam and the other (R/W) for high beams. You could just tap into the low beam wire and run it to both low beam headlights and do the same thing for the high beam wire for both high beam headlights and you could use the original relays and factory wiring for the most part.
The dimmer relay has two wires coming off of it that runs to the headlights, one (R/B) for low beam and the other (R/W) for high beams. You could just tap into the low beam wire and run it to both low beam headlights and do the same thing for the high beam wire for both high beam headlights and you could use the original relays and factory wiring for the most part.
That is what is intended.
But the thing is I want 4 lights for Hi beams since the system does not have the HI filament in the headlight to make it a brighter bulb.
If I left the 2 LO's on all the time and used the HI position to activate the 2nd relay then it would allow 4 lights.
But the thing is How to isolate the lights from the switch to prevent burning it out,so that is why the relays are being used.
Making the 1st relay a "always on" will allow 4 lights.The Stock switch would kick the HI's in,and when switched to LO go back to a already activated relay.
Not sure I fully understand but do you want two headlights for low beam but four headlights for high beam? Lets say that's the case. If so, then the low beam wire from the dimmer relay runs to the two low beam lights where as the wire from the dimmer relay for high beams runs to all four light such that two lights (used for low beams) have two wires wired to one terminal (one for low and the other for high). When the high beams are activated the voltage from the dimmer relay for low beam activation is disrupted and the wire for the high beam takes over.
I spent like 30 minutes writing a post in quick reply and quickly deleted it because I realized that, in words it's too damn confusing. I'll make you a diagram in multisim and post it. SOOOO much easier to follow.
..ah..ya..
I keep thinking that the HI circuit will backfeed into the LO..
So wire One relay as LO..hooking to 2 lights only.
Then take and wire all 4 lights into the HI Relay...same basic wiring.
Since the circuits separate by the "coil" in the relay,when the LO is OFF then it doesn't have any connection to the lights.
That allows me to Hook up FOUR lights to the HI relay and run four lights as HI.
your diagram doesn't depict automotive relays, but more electronic ones. it looks confusing to me.
the factory relay is a 12V toggle output to the headlights, ground is common and always present.
to be safe you should have 4 relays as above if you plan to run hi and lo all at the same time while on the hi setting, use the factory wiring as the control circuit for the new relays.
Last edited by RotaryEvolution; Jun 22, 2016 at 05:15 PM.
I was able to get some 100 watt H3 bulbs..(Bzzttt!...ow my retinas..lol!)
So instead of screwing with wiring 4 lights I went with 2@55 for LO and 2@100 for HI.
I spent like 30 minutes writing a post in quick reply and quickly deleted it because I realized that, in words it's too damn confusing. I'll make you a diagram in multisim and post it. SOOOO much easier to follow.
our fab guy makes really funny faces when you try to explain relays to him
I pulled up a wiring diagram off Identifix and used a simplified version that probably will work for you.
Just wire in a standard 4-pin relay to power the Low beam side when the dimmer switch is on high beam. You can put the relay spliced into the existing 30A headlamp fuse, or go off of the battery with a dedicated fuse.
The FC dimmer switch is unique where it switches solely from low to high through the factory 5 pin relay, so that's why I just added a simple 4 pin in parallel to accomplish what you want.
personally i'd just wire up 2 relays and use all the existing vehicle wiring, taking the load off the switch.
add a 10g wire, split to 2 12 gauge wires to pin 30 off each relay from the battery as a feed
ground pin 85
switch side red/white wire to pin 86 of relay 1
switch side red/yellow wire to pin 86 of relay 2
headlight side of red/white wire to pin 87 of relay 1
headlight side of red/yellow wire to pin 87 of relay 2
but i guess that doesn't count running both high and low in tandem which would require another pair of relays.
Last edited by RotaryEvolution; Jun 26, 2016 at 09:42 PM.
this is a crude drawing of the way I did it.
I'll feed 12 volts by either the battery or ignition switch.
The relay coils get power from the headlight connection.
Thank you SIRI for making us stand on our heads to read the damn drawing!
I would recommend coming off the battery with at least a 30A fuse. That is quite a bit of draw to run through the switch itself. I have been in the process of going through my harness to try and decrease the electrical load on the ignition switch. There is only so much it can take for so long. This is why newer cars use a body control module and the IGN switch is nothing more than two to five 18 gauge wires that go to the BCM and the BCM commands everything else on.
The headlight switch only operates the relay coils so it is far less than what they were running before(headlamps).Since the headlight system is fused in the Fuse block I should not have to worry about that.The old wiring feeds the relay coils at the headlight connector.
On my last car,The power to the lights came from the Battery.It had a 4 lamp LO/HI system but then again the headlights were the 3 wire bulbs..meant for LO and HI in a single headlight.
That system was Super Kick ***..it gave you excellent night driving vision.
The Positive cable will come up front anyways to the "old style" Starter solenoid,so I am gonna swing a cable over to power the lights and E-Fan.
I got an idea of running it through the fuse block too..
Anyhow,Got the lights set in,wired to the engine bay and ready to Paint around the front of the car..finally.Once I get Power established then I can adjust the lights for angle and put the buckets on..For Good!
personally i'd just wire up 2 relays and use all the existing vehicle wiring, taking the load off the switch.
add a 10g wire, split to 2 12 gauge wires to pin 30 off each relay from the battery as a feed
ground pin 85
switch side red/white wire to pin 86 of relay 1
switch side red/yellow wire to pin 86 of relay 2
headlight side of red/white wire to pin 87 of relay 1
headlight side of red/yellow wire to pin 87 of relay 2
but i guess that doesn't count running both high and low in tandem which would require another pair of relays.
Wanting to run a set of 4 (2wire) lights on high beams as well....with the easiest wiring solution...if I'm looking at this correctly.... with two relays it will work if the high beam relay is ganged to both the high beam light and the trigger to low beam relay(pin 86) off of pin 87 side...I could pull the power off the hot side of the headlight motors for pin 30 as I'm not using them...no factory wire/connector hacking required and off loading the stock switch/relay system as a bonus...this sound reasonable?
just saw this thread again when someone bumped it.
This is a shot from last year before the car went into "hibernation".
It still needs some work,but you get the idea of what I am Building..!
