Voltage Drop - Fusebx relocation

Discussion in 'Maverick/Comet Projects' started by mojo, Jun 6, 2011.

  1. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    I've been using the grn/red tracer wire that was formerly used to key orig alt on/off to key my elec fan. Originally I was getting 12v frm that wire. Yesterday I started havin an issue w/ the fan not workin properly. I been usin that setup abt a year now - no issues. Im using a one wire 3G now so did'nt have any other use for that wire. When I got home frm the car show I was not up to workin on it - after out in heat all day.

    Anyway, today I discovered I am only getting 2-3volts frm that wire. I suspect there is corrosion/rust somewhere in that circuit. I know 2-3v ain't enough to trigger and hold the relay. I hooked a 12v jumper direct to the pos on battery. I heard the relay click and hold. The first place I will look when it cools off "93 here today'" is the fuse panel for any corrosion.
    I am considering relocating my fuse panel under hood. If so, I will probably use a marine grade panel. Any, ideas/suggestions on the above mentioned issues?
     
    Last edited: Jun 6, 2011
  2. injectedmav

    injectedmav Member

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    No corrosion, the circuit is the ground for the alternator light. If you put a relay in line, it creates an additional load and thus additional voltage drop. You now have a series circuit with a bulb and relay coil as 2 loads if that make sense. You might also create problems in the charging system as that is the key on input for the voltage regulator(which is responsible for grounding the light through the regulator housing).

    Use the red/grn wire that feeds the instrument cluster for the fan relay.
    other wires that are hot with the key on from the ign sw are: white/purple, black/green. If you pick up the red and green in the engine compartment, you have a in line resistor wire for the coil and your voltage will be limited to 6-9 volts. You need to get that wire before the resistor or use a different circuit.
     
  3. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    OK my friend - thanks for the info.

    You now have a series circuit with a bulb and relay coil as 2 loads if that make sense. What ur saying is kind of confusing but I am going to take ur advice.
    Question on the white/purple wire mentioned? Did u mean wht/blue? I have one of these ClassicCarWiring color charts and don't see it there - cud there be an error on the chart? I do see Blk/grn. Anyway, I will look for that wire when I try and fix the problem.
    The car was converted to DuraSpark ign by some previous owner and im not sure abt the wiring. Everything looks factory for the most part except for the ignition sw. If the car is running and u turn it straight to accy position it will continue to run -- Any ideas on that dilema?
    The charging sys seems to be still workin fine - I hope I did'nt damage anything else.
    Thanks for ur response and advice. I really appreciate ur advice. I plan to eventually replace the orig fusepanel w/ one that has more circuits and move it to a more accessible place, but, for now I just want to ride.
     
  4. injectedmav

    injectedmav Member

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    The white with purple or violet (maybe faded over time) is the accessory feed for the radio and possibly other smaller amp accessories. The black and green wire is usually a higher amp accessory (ac, blower motor, etc) feed and if you're only triggering a relay, it probably doesn't matter which one you use. I just checked on my car and the wht/pur is going to the radio. However, I cannot find it in the diagram so there may be something to what you're saying about inaccuracies. I'll have to do some checking and see which might be the best to use. I'm sure someone else may chime in with some other ideas as well. According to the diagram, if you tap the green with red wire at the ignition switch, you should have power as it shows that it is on the same terminal as the black and green. There are also 3 other green and red wires that I found on the diagram so the accessory feeds are probably your best bet.

    As far as it running if you go straight to accessory: it sounds like someone wired the duraspark box or the coil to an accessory feed instead of the run circuit or there is a back feed from the run circuit to the accessory feed. Could be tricky to find depending on the complexity of your mods. Only the black and green wire should be hot with the ign sw in the accy position. The red/grn feeds the coil and is the "run" circuit and is hot in run only. This is all based on a 72 diagram and might be slightly different for your 73.

    Hope this helps:tiphat:
     
  5. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    Ok! What u have pointed out makes sense. I'll just have to work w/ it until I have it worked out. I'll get back on it as soon as the heat let's up, 96 here today. Anyway, I have temp fused jumper w/ a trailer plug I can hook to the battery so I can use the car till I find the circuit I need.
    What confused me was the grn/red alt wire worked for a year; the only reason I put it there is cuz I got 12v initially.
     
  6. injectedmav

    injectedmav Member

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    you mentioned you had a 3G 1 wire conversion. If the regulator plug was just deadheaded, that would leave the end of that circuit open ended with power on the other end, indicating 12v with a meter. Then again, I'm guessing that the grn/red you have is the regulator wire. It could be one of the others that I mentioned in that last post after seeing the diagram. One of those goes to the brake light switch if it's inside the car. I don't remember about the other one, but I do remember seeing a resistor wire in one of them. If you picked it up in the engine cmpt, I would bet it's the regulator wire tho.
     
  7. Jsarnold

    Jsarnold Senior Member

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    Everett,

    If you have electornic ignition that can use full 12V, you might want to consider putting an expansion fuse block under the hood. I have one that has 3 or 4 circuits that are switched with the ignition key and 3 or 4 (can't recall which is 3 and which is 4) that are always hot. That way you have plenty of switched and unswitched circuits for whatever you need. I used the wire from the ignition switch (thru the resistor wire) to the distributor to switch the relay for the 3 or 4 switched circuits. The 6-8 volts are sufficient to switch the relay.

    So far I've used switched circuits for the elect choke and HEI distributor and unswitched circuits for the elect radiator fan and (dual) horn relays. Plan to use another unswitched circuit for headlight relays some day.

    If you want to consider it, I can get you some details and pictures.

    Jim
     
  8. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    Thanks for ur input Jim.

    I have DuraSpark and I measure abt 6+V on the + side of the coil. I don't know if the DuraSparks work w/ 12V or not; the last time I was involved w/ Fords or car hobby was decades ago when points were in.
    I have an expansion fuseblock on the interior that's switched w/ 6 circuits. I am only using 2 of those circuits at present, elec choke and stero reciever. I just have one (non-sw) inline fuse to the battery for stero memo.
    Which wire are u using on the dizzy? What dizzy are u using?
    Yes - am interested in whatever suggestions/ideas u have to share. U can send it here or PM, either way appreciated.
    Trying to get my gremlins sorted out - hopefully to make it to the RU.
     
  9. Jsarnold

    Jsarnold Senior Member

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    I have an HEI (GM style) distributor with integrated electronics and coil. Its powered by one of the 12V switched circuits on my expansion fuse block.

    I don't know what voltage the Duraspark needs or how it should be wired but I'm sure you can find that info on this site or elsewhere on the Internet. If it needs the reduced 6-9 volts, and your original Red/Lt Green wire that originally went to the coil is still there I'd use it. If it needs 12V I'd use one of the sw circuits from your expansion fuse block.

    Then your car shouldn't run when key in in ACC position.

    I'd use another of the sw circuits from your expansion block to switch the relay for your elect fan. That should get you the full 12V you need there.

    Did your fan run continuously with key on, i.e., no temp control?
     
  10. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    My fan is controlled by a rad mounted probe on a adjustable sw circui; it does not op continuously.

    I cud use the exp blk to sw fan relay.

    I'll ck the DuraSpark site and see what I can gather frm that source.


     
  11. Jsarnold

    Jsarnold Senior Member

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    I used a non-switched power source for the fan controller. Fan runs a few times for a short while after the engine shuts off. I THINK the controller I got has a delayed shut off so the fan can't run the battery down when engine is off. I looked at a few controllers -- at least one had that feature.
     

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