I got a set of these for driving lights...
I want to wire them up so the fluted side will come on with a switch, and the other side will come on either with a switch or with the high beams. I know the high beam switch switches Ground rather than 12V, but I decided not to tap the ground at the switch and went and looked at the headlight connector. When the high beams come on, that wire goes "hot", right?
WRONG!
with the key off, there is nothing at the headlight connector. With the key in the ON position, there is +12V on ALL connections. So:
........._ 12v
12v |......| 12v
All three have 12V. When you turn the lights ON, low beam:
......._ 12V
0v|.......|12V
And on high beam:
........_ 12v
12v|......|0v
I have H4 single bulb headlights.
Now, it came with a special switch:
With 4 connections on the back
O _ _G
I _
O _
I being 12V In and the two Outs going to the inboard and outboard bulbs.
So, the outboards I want on or off with a separate switch, and the inboards on by themselves or with the high beams.
So, I figure to take 12V and go to the top O, and send I to the "hot" side of the relay. Then take the 12V from the right side of the headlight connector (that is at 12V when the high beams are ON, thereby turning the low beam filament OFF) and send it to the bottom O on the switch.
I never figured it worked like this. Any device works with a "difference of potential". When all legs are at 12v, there is no difference of potential. All legs are at the same voltage, so no current flows. When you turn the switch on, one side goes "low" (ov) and provides a difference of potential and that filament turns on. Likewise for the high beam. You are switching the ground from one filament to the other.
I'm a bit reluctant to wire it up this way. In theory it should work. I think the best idea is to tap the always on terminal at the top for the 12v to the top (O)utput, so the difference in potential is coming from the same place.
Anybody have an idea how this works, wiring diagram and the pinouts for the headlight connectors, so I have a better idea? I am also going to add a fuse on the Ground side of the relay, just in case...
I want to wire them up so the fluted side will come on with a switch, and the other side will come on either with a switch or with the high beams. I know the high beam switch switches Ground rather than 12V, but I decided not to tap the ground at the switch and went and looked at the headlight connector. When the high beams come on, that wire goes "hot", right?
WRONG!
with the key off, there is nothing at the headlight connector. With the key in the ON position, there is +12V on ALL connections. So:
........._ 12v
12v |......| 12v
All three have 12V. When you turn the lights ON, low beam:
......._ 12V
0v|.......|12V
And on high beam:
........_ 12v
12v|......|0v
I have H4 single bulb headlights.
Now, it came with a special switch:
With 4 connections on the back
O _ _G
I _
O _
I being 12V In and the two Outs going to the inboard and outboard bulbs.
So, the outboards I want on or off with a separate switch, and the inboards on by themselves or with the high beams.
So, I figure to take 12V and go to the top O, and send I to the "hot" side of the relay. Then take the 12V from the right side of the headlight connector (that is at 12V when the high beams are ON, thereby turning the low beam filament OFF) and send it to the bottom O on the switch.
I never figured it worked like this. Any device works with a "difference of potential". When all legs are at 12v, there is no difference of potential. All legs are at the same voltage, so no current flows. When you turn the switch on, one side goes "low" (ov) and provides a difference of potential and that filament turns on. Likewise for the high beam. You are switching the ground from one filament to the other.
I'm a bit reluctant to wire it up this way. In theory it should work. I think the best idea is to tap the always on terminal at the top for the 12v to the top (O)utput, so the difference in potential is coming from the same place.
Anybody have an idea how this works, wiring diagram and the pinouts for the headlight connectors, so I have a better idea? I am also going to add a fuse on the Ground side of the relay, just in case...