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Old 11-02-2004, 04:29 PM
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relays on head lights

I bought the Ezwire kit and just starting on it. I was told I should use relays on head lights and I don't know a dang thing about them or how to install them. I been trying to call Mad electic but have not been able to get through. There web sight said the owner has been sick. Can some one tell me how to install them and were to buy them. I'm getting know where.
Does the break light need them ??? Is there any books out there that can help a rookie.

Thank you

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Old 11-02-2004, 04:45 PM
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Think of a relay as a switch. What you're doing when you use a relay is to use a small voltage to flip a switch that can handle a heavier voltage. Therefore if you use a relay on your headlights (you need one for high beam and one for low beam) then you'll be pulling a full 14+ volts (usually from a distribution buss) directly to the relay and tripping the relay with a signal from your light switch which will be somewhat less than 12 volts (probably about 11.2). This will make a big difference in the brightness of your lights.

Here's the article on MAD electrical's web site that explains why you want to use relay's on headlight circuits. Also read his other articles they are quite informative. I would not purchase your relays through MAD though. He has been sick and it will take forever to get them. You should be able to pick them up from your local Napa dealer or local auto parts store a lot cheaper.
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Old 11-02-2004, 09:32 PM
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To learn more about relays go here.

Then for wiring diagrams go here.

The site is for 60-66 GMCs but the diagrams are universal.
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Old 11-04-2004, 09:26 AM
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Some systems don't light the low-beam filament when the high beams are selected. One thing you can do when you use relays is to power both filaments when the high beams are selected.

Here's links to a couple of sites that I've found in my travels with lots of handy relay examples: <-links to examples are about halfway down the page.

Forum member Horvath has some info online as well:
When life hands you lemons, ask for tequila and salt
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Old 11-04-2004, 09:36 AM's Avatar Moderator
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Here is another trick you can do with headlight relays.

'53 AD extended cab how-to29
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