E-Code wiring question

Discussion in 'General Motoring' started by Jamie, Mar 30, 2006.

  1. Jamie

    Jamie Guest

    I've studied the diagrams and have read a few installation stories, but
    I am not quite clear on one issue.

    Am I correct to plan to wire the e-codes as follows?

    1) [Fact] A wiring harness extends from the firewall to the headlights
    on both sides, there are two harnesses - one harness per side.
    A) [Fact] I plan on wiring from my battery, it is on the
    passenger side. Therefore, this will be the side with the relays.

    B) On the driver's side, I will use the existing wiring for the
    turn signal and running light and NOT use the wiring for the high/low
    beams. These wires will be terminated (not connected to anything).

    C) On the passenger side, I will use the existing wiring for the
    turn signal and running light. I will use the headlight wiring to
    connect to the relay/wiring kit. The low beam wire will go through a
    fuse to the low beam relay and the high beam wiring will go through a
    fuse to the high beam relay. From there I will connect the respective
    wires to the headlight on the passenger side and jumper the wires and
    extend the wiring across the front of the car to the driver's side to
    connect over there.


    Does this sound right? The two main questions are: do you only use one
    side's harness for both sides' headlights? Second, if so, are there
    separate wires on each side, 1 for high, 1 for low and 1 common?

    Thanks!
     
    Jamie, Mar 30, 2006
    #1
  2. Jamie

    Jamie Guest

    Sorry, follow up question:
    Does my 1987 Volvo 740 have a "ground-switched" headlamp circuit? I
    noticed a ground wire on each side coming from the harness. This
    grounds to a bracket mounted on the quarter panel - 1 per side.

    Must I follow Dan Stern's instructions for this type grounding, or does
    it not apply?
    He states:
    "SPECIAL CONSIDERATIONS FOR GROUND-SWITCHED SYSTEMS

    Many Japanese vehicles, as well as a few others, use a
    "ground-switched" headlamp circuit. In these circuits, the headlamp and
    beam selector switch break or complete the ground side of the headlamp
    circuit, rather than the feed side. On these systems, it's imperative
    to use both negative and positive existing headlamp wires to trigger
    the relays. It is tempting to run the existing headlamp feed wire to
    relay terminal 86 (trigger feed) and simply find a convenient ground
    for relay terminal 85 (trigger ground). However, this will not work
    with ground-switched systems. Run the vehicle's existing feed wire to
    terminal 86, and run the vehicle's existing ground wire to terminal85.

    Now, what are we going to do now that we've used-up our one and only
    ground wire on the 85 terminal of the low beam relay, but we still have
    to install the high beam relay? Go to the other side of the car and you
    have another ground wire! Remember, the relay trigger circuits can be
    as long as you like, because they take insignificant power. So, you can
    extend the vehicle's existing headlamp wires to your relay mounting
    location. It is fine to use this method regardless of whether you have
    a ground-switched system or not, so go ahead and use it if you're not
    sure. "

    http://danielsternlighting.com/tech/relays/relays.html
     
    Jamie, Mar 30, 2006
    #2
  3. Jamie

    James Sweet Guest


    You'll want to bridge the harnesses between the two sides, you can do
    this easily enough with some of those insulation piercing connectors
    under the fuse box right at the bulb failure sensor or you can run wires
    across under the hood, this will prevent the headlights from tripping
    that but retain functionality where you really need the failure warning,
    for the taillights.

    Yes there's wires on each side just as you describe.

    You don't need to fuse the headlight wires to the relays, they're
    already fused at the fuse box (I think?) actually it never hurts to have
    another fuse. *DO* fuse the wires straight off the battery before the
    relays though. I got some nice waterproof inline fuse holders at Schucks
    when I did mine.
     
    James Sweet, Mar 31, 2006
    #3
  4. Jamie

    Jamie Guest

    Thanks james. I wasn't sure about that headlight failure light.
    Bridging sounds like a great idea. How did you ground yours? I see a
    grounding bracket on each side with 1 if not 2 wires being grounded.
     
    Jamie, Mar 31, 2006
    #4
  5. Jamie

    James Sweet Guest


    I bridged mine under the hood, I mounted the relays back next to the
    power steering fluid resivoir and ran wires enclosed in flex tube. If I
    were to do it again, I'd bridge the sides at the lamp failure sensor.
     
    James Sweet, Apr 1, 2006
    #5
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