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.
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.
