Offroad Lights Install Question

Discussion in 'Chevy Truck Accessories' started by drtbkmxr, Jul 26, 2008.

  1. drtbkmxr

    drtbkmxr New Member

    I have a 1989 Chevy Blazer I have spent the past two years building. I have added a chrome tubular push bar on the front of the truck and attached 4 off-road lights. I need to wiring in these lights but I have a few questions.

    I realize I need to run at least 2 relays for the lights. The lights are 100W so they should pull about 8 amps each.

    Now here comes the question. I want to run these lights to a (one) three way switch. This switch will be used for Off/On/Highbeam On. Got your attention now huh? I want to be able to wire my lights into the high beam switch. How can I do this successfully? I have located the wire for my high bean and now need to know the best way to preform this action?

    Do I need to upgrade my stock alternator to safely run these lights? Do I have to purchase a seperate fuse block to safely wire these light in or can I simply use an inline fuse? If so what size wire should I use and what size fuse? is the best place for the relays close to the power source like I have read in some forums or does this matter? If it does matter where would the best locations be for the relays and the fuse(s)?
  2. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    To run the lights the way you want you'll need two relays per light set (2 lights per set).

    Relay 1 On:
    Battery to relay
    Relay to lights
    Relay signal wire to full time hot

    Relay 2 Highbeam:
    Battery to relay
    Relay to lights
    Relay signal wire to Highbeam wire

    Switch gounds to under dash chassis
    Light grounds to a good under hood ground or the battery negative post.

    Both Relay to light wires (per light set) need to be spliced together at/near the lights.
    Use 15 or 20 amp inline fuses.
    Relays are best when placed as close as possible beween the power source (battery) and the end user (lights), in a dry place (use marine relays and wire connectors if you can since this is a 4X4 and may involve getting wet underhood).
    For wire I'd use a 10gauge or better (but I tend to overbuild usually when wiring things).
    For a good job tin all wire ends and soldier connections if possible to preclude any shorts.
  3. drtbkmxr

    drtbkmxr New Member


    Thank you so very much that helps me out. I started to re-think my plan for the lights after reading your response. I'm wondering if I shoud just cut out the 3 way switch and run a two way switch for on and off right off the high beam wire.

    The whole reason I'm using the lights is for better night driving. I live in Arizona and the streets are not well lite out this way. Kids in the area are constantly walking around at night in the streets wearing black of course and we have no side walks. I want to get the most visubility possible. I want to wire these into the high beam switch for ease in kicking the lights on and off for on coming traffic. This is a truck I have built for my parents and I know they won't use the lights if they are not hook up directly into the high beam switch.

    This being said if I wire the lights using 2 relay's with a 2 way switch using the high beam wire as my hot lead and I should not have to use a power source from the battery. Should I still use and inline fuse between the power source and relay or will the high beam fuse in the fuse block be sufficient? Should I increase that fuse to a 20 amp fuse? Will the wire from the high beam switch used to power to the 2 way switch be suffcient enough to support the extra load? From the switch out to the relays and then to the lights still use a 10 gauge wire?

    I figure with the 2 way switch from the high beam power wire I will still be able to cut power to the lights all together and still have use of the trucks regular high beam lights.

    Does this sound possible?

    Thanks for your help

    Last edited: Jul 27, 2008

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