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Evenin' Guys,
As we all know, the factory lighting on our CJs leaves a lot to be desired, especially the headlights. The main problem is how they are wired. The power runs from the battery thru the dash to the switch, then from the switch all the way out to the lights. The factory used small gauge wires with highly resistive contacts for these lengthy circuits, which causes an excessive voltage drop at the headlights.
The solution is to shorten the power path by using relays, which are simply an electrical switch. When the relays get power from the headlight switch, they complete a circuit from the battery directly to the headlights. Since this new circuit uses heavier wire, fewer contacts, and is a shorter distance from the battery to the headlights, the voltage drop is virtually eliminated.
Here are before and after wirings diagrams from Daniel Stern's excellent writeup on the upgrade.
Matt
As we all know, the factory lighting on our CJs leaves a lot to be desired, especially the headlights. The main problem is how they are wired. The power runs from the battery thru the dash to the switch, then from the switch all the way out to the lights. The factory used small gauge wires with highly resistive contacts for these lengthy circuits, which causes an excessive voltage drop at the headlights.
The solution is to shorten the power path by using relays, which are simply an electrical switch. When the relays get power from the headlight switch, they complete a circuit from the battery directly to the headlights. Since this new circuit uses heavier wire, fewer contacts, and is a shorter distance from the battery to the headlights, the voltage drop is virtually eliminated.
Here are before and after wirings diagrams from Daniel Stern's excellent writeup on the upgrade.
Matt
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