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TTG shawty
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This is a 1942 chevy truck and I'm changing the wiring up... they have the headlights ran to a toggle switch tied in with the ignition so I picked up a universal headlight switch and floor mounted hi/lo beam dimmer... heres a diagram of what I have basically, but where do I need to add the relays? Or do I really even need relays? the Headlight switch is fused already... I was just curious if I need the high and low beam relays before the dimmer switch (between headlight switch and before dimmer), or after the dimmer switch (after dimmer switch and before head lights)...

42headlightwiring_zps20287f71.png
 

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TTG shawty
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3,101 Posts
Discussion Starter #2
Disregard the turn signals as they are working and dont need any changes... also, I have no idea why there are 2 pins for tail lights on the switch I bought.
 

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you can get away with out relays

if you do add them you put them between the headlights and the dimer switch

got a link to the headlight switch?
you should/could have depending on the switch
12v in
out to the parking lamps (pulled 1/2 way out)
out to the head lights (pulled all the way out)
variable out to the gauges
and a pin that gets grounded to turn the interior lights on
 

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TTG shawty
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3,101 Posts
Discussion Starter #4
I bought it at Autozone, doesnt pull up on the website. Once I get power to the switch when I'm ready to install I'll see whats up with the two tail light prongs and may use one to power the guage lights... so you dont think I need relays? I thought relays were there to protect things?
 

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The relays would go where the headlight switch is. You would need 3. One for head lights, one for tail lights and one for park lights (if you want it all seperate) you then power the switch, and use the output of the switch to turn on the relays for the appropriate feature.

Basically battery to relay to light. Then the switch turns on the relay. The only diffrence would be the headlights. They go battery to relay to dimmer to headlight
 

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The relay doesn't necessary protect things. They just act as a current switch. You can use a small wire to control the relay which powers a larger power device. A good configuration would still have fuses on both the control and the device power wires, as close to the power source as possible.

If the wiring and hi/lo switch is rated for the amperage the lights will use, then there really isn't need to add relays. However, depending on the gauge of wire, you could gain a little light by having less voltage drop in the wire by putting the relays near the lights and having the power wires as short as possible under the hood.
 
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