Register now to get rid of these ads!

Technical Headlight Relays??

Discussion in 'The Hokey Ass Message Board' started by jaw22w, Dec 25, 2019.

  1. JerryTball
    Joined: Dec 2, 2020
    Posts: 21


    you know, I have to be honest I have not owned a car that you could actually work on that didn’t have a computer since the 70s. With the exception of the new mustangs you can get under the hood and do some stuff and not mess the computer up too much. My 40 Ford is the first car since the 70s that has distributor, four barrel carburetor with a coil LOL. I am by no means a mechanic of any kind and today I took care of a couple of things one if I drove the car and it sat for maybe 15 to 30 minutes it was real hard to start basically carburetor boil. So I put the spacer in there runs great now. But I could not figure out how to get the license plate light to come on. Previous owner said just jiggle the wire LOL and that didn’t work but I ended up taking it apart. It’s just a single wire runs to the license plate holder. But I noticed the wire had a little cut so I’m thinking as it touched metal it worked and then it didn’t work. But after I fixed it it still didn’t work, so I noticed my license plate bracket really doesn’t touch any metal on the car so I ran a wire from one of the nuts on the back of the license plate do a little screw near the bumper..... hey it works now, my first electrical experience really like I said I’m not a mechanic at all.. So the other day my battery did end up being bad and I put in one of the good yellow optima batteries and now my voltmeter reads a nice 13 to 14 before it was like 10 and 11, but I had a question before I fix that license plate I did notice that it was not indicating like that 13 and 14 it was stay in more like 11 to 12 cut that short or whatever in that license plate light cause that voltage drop just curious,? Thanks

    Sent from my iPhone using H.A.M.B.
  2. Wrench97
    Joined: Jan 29, 2020
    Posts: 323


    Probably just voltage drop in the connections, + or negative side.
  3. Steves46
    Joined: Sep 23, 2008
    Posts: 434

    from Florida

    Are you running 6 or 12 volts. Either way, make sure your grounds are good. I suspect the original headlight switches were rated for whatever headlight that were available. I can understand why a relay would be needed for a more brighter bulb such as halogen. The switch would have a tough time with the load.
    Last edited: Dec 12, 2020
  4. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 841


  5. Mr T body
    Joined: Nov 2, 2005
    Posts: 2,180

    Mr T body
    Alliance Vendor
    from SoCal

    The reason is so the relay block can have power all the time and not switching individual relay feeds.
  6. Joe H
    Joined: Feb 10, 2008
    Posts: 1,000

    Joe H

    You don't have to run a 50 amp fuse or 12 gauge wire, but you need enough wire and amps to power the head lamps properly. If the wire is long, then bigger is better, 50 is overkill, but the point of this is to supply the lamps with full battery power. Figure on 10 or 12 amps with two lights on bright, plus the initial surge of turning them on, and 25 to 30 would be about right.
    The relay is simply there to take the load off the old wires and switch, so adjust the wire size, amperage, and relay size according to your lights. But, no matter how you wire the relays and lights, you still need to pull power right off the battery to eliminate as many connections and old wire as possible, if you don't, then whats the point?
    Last edited: Dec 12, 2020
  7. Wrench97
    Joined: Jan 29, 2020
    Posts: 323


    Did you read post #1?

    The point is to move the dimmer switch off the floor.
  8. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,181

    from Indiana

  9. alanp561
    Joined: Oct 1, 2017
    Posts: 1,488


    The owners of the last semi I drove moved the dimmer switch off the floor up to the turn signal stalk without telling me. I had a hell of a time getting my foot up there.;)
    Algoma56 and Wrench97 like this.
  10. Joe H
    Joined: Feb 10, 2008
    Posts: 1,000

    Joe H

    I changed the numbers, it's just one way of wiring relays. Headlight relays.jpg
    AHotRod likes this.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.