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Halp Electrical people, help with a car project?

Discussion in 'useless chatter' started by Mr. Asa, Jan 22, 2013.

  1. Ok, so you've got some life events. The move would be the biggest detractor for me so I get where you're coming from there.

    We may have only a fraction of the story, but you have three people who are very comfortable with electronics telling you its better to repair the existing infrastructure than run new stuff. Experience counts for something, whether you choose to believe this or not.

    Your example is not valid. If I'm doing a job for a customer, I would be doing it to their specs for colors/materials. As the craftsman contracted for the job, the method of execution is up to me. If the customer wants to try and tell me my methodology is wrong, they can pound sand, unless they themselves are considered a resource in the topic. If a master upholsterer told me I was doing it wrong, I would listen and ask for assistance.

    I equate your question to a rookie tech asking a master tech how to accomplish a task. You however continue to justify why your view is superior to the expert opinion you sought in the beginning without presenting anything more than "I don't want to do it that way" as rebuttal.

    For someone who has proclaimed them self to be competent in reading schematics and troubleshooting circuits, you are sure going out of your way to not even attempt this.
  2. Experience does count for something. My experience gained from working as a mechanic and having to previously repair and partially replace a several automotive harnesses (including a HMMWV that got fucked up because a previous mech did not secure it and a log fucked it) coupled with my intimate knowledge of this car tell me that it is a losing proposition to repair the stock unit.

    My example is valid. I am the craftsman doing the work. I am the customer giving the specs. I am the alpha and omega of this project.

    Reading and troubleshooting is not the same as building a circuit

    You know what, fuck it. Why are you even arguing this anymore? You obviously don't want to help me with my project, are you bored? Did I inadvertently piss you off about something? If so, I apologize. Fuck
    Why are you arguing this? What have I done to make you argue against me doing it my way so vehemently?

    Please, just answer this:
    Knowing that you have never seen the car, knowing that you have no knowledge of the car or the condition of the harness other than what I have given, why are you so convinced that you are correct?
  3. #23 CletusJones, Jan 24, 2013
    Last edited: Jan 24, 2013
    In one sentence: I despise doing things more than once.

    As someone who has been doing automotive electrical work for a long time this is something I'm passionate about. I cannot stand homegrown hackery.

    Using the standard systems allow for easy troubleshooting and serviceability. There's no way you'll remember what's what in 6-12 months with something homegrown unless it's ridiculously labelled and documented, which takes lots of time. (More than 3 days IMHO doing it right) What if you're away from home with no tools or schematics and there's a failure? You've already said you plan to solder instead of crimp...

    If you were to rebuild the harness, you could add in the extra capacity and replace the hacked up bits as needed. You could relocate all the wiring for your switch plate at once for a clean trouble free install. Any number of modifications can be made with ease.

    I built, tested, and installed an entire new electrical system in my uncle's '66 mustang; there's not much to it. We pulled and reinstalled the harness, laid it out and went to town. In one shot we went from pure crap to a perfect (factory correct) harness. We even created a separate harness for the audio system and hid the components so nothing is visible. Why reinvent the wheel when it's a 3-5 day project tops to pull, repair, and reinstall the harness? If you truly got enjoyment from working on this vehicle as you said, the feeling of pride in craftsmanship would be enough to justify the extra time and attention to detail.

    Either way you're going to do whatever you want, and I have no vested interest other than that of a mustang fanatic and general auto nut. You came here asking for opinions and that's what you got. I'm sorry they're all different than yours. If you want help designing your circuits, post a rough circuit diagram (with approximate impedance values) and I'm sure we would all be happy to help you with the math.
  4. So the H4 bulbs are rated at 55/60W and at 12V they should pull 5A, so according to this:
    If I have two 60 watt bulbs, 14 gauge is the smallest I can use safely if I have a separate circuit to each bulb.

    So 10A fuses would be right at the limit for the circuit, with 15A leaving a little wiggle room?
  5. #25 CletusJones, Jan 24, 2013
    Last edited: Jan 24, 2013
    Are the lights in parallel or series? What other resistance loads are on the same circuit?

    Edit: each sealed beam (there are 4) in my E30 is 60-65 watts and has it's own 7.5A fuse. What's Ford's stock fuse rating for that circuit? I think yours would be similar in design, yes?
  6. Definitely not series, if one goes out I don't want to have the other die (although having high beams might negate that, but I don't want to rely on it), was thinking parallel but then I would have to go with 10 or 11 gauge wire?
    No other loads on the circuit, switch will power the coil of the relay, bulb will go through a fuse and the closed contact of the relay.
  7. Use a 20A fuse, 30A rated relay. 12AWG from battery to fuse and fuse to relay, and a run of 14AWG wire from the relay to each headlight. Mind you, I overbuild things :) 15A fuse, 20A relay, 14AWG/14AWG should be OK.

    Use good stranded wire with lots of strands and good flexibility, and make sure it's well secured to the car.
  8. If you're really going to overbuild, might as well run 12awg from the relay to the headlight as well. Might give him some better light output as well.

    and the last part is probably the most important, since you are going to be soldering. You don't want any undue fussin'
  9. Asa's car is hot shit. I can now attest to this. :)
  10. Any reason to not combine the ground for the relay's coil?
  11. If the combined ground comes loose, you could get +12V flowing through the load, through the relay coil and into the relay control circuit.

    If there's only a single switch supplying a switched +12V to the relay coil, you should be OK. If there's other relays on the same circuit, etc.. I'd keep the grounds separate.
  12. Separate switch for high and low-beams, which is why I was thinking it might work.

    I'm also pondering how to include the tail-lights in the circuit.
    Basic circuit looks like:

    But it is doubled as there is a separate relay for high and low.
    Since there is a separate switch and relay for high and low, I'm wondering how to link it
  13. I'll draw something up - might be sunday before I get to it, got friends flying into town shortly
  14. How about just using a double-pole double-throw switch?
    If I could find one that was on-on I would be set.
  15. I've been thinking about the setup for the high-low beams, I don't like the idea of turning one switch on and turning the other off, would rather it be automated.

    Since I'm using 5-pin relays, 87a is a terminal I can use, I'm thinking about setting it all up so that switch #1 sends power to the second relay, and whether switch #2 is powered determines whether the the power goes through 87 or 87a, therefore the switch #2 will choose high or low beams.
  16. #36 Mr. Asa, Apr 19, 2013
    Last edited: Apr 19, 2013
    Random thought I tossed together.
    I think I left out a fuse between 87 on Relay 1 and 30 on Relay 2, but I'm not sure if it's really needed since it's already fused once?

    First switch is a DPDS
  17. Does the mustang have a 'pull for high beams' switch on the column that you'll want to keep working?
  18. It's a foot button, top left of the driver floor
  19. It's got a foot-switch, but no I am not focused on keeping it.
  20. Pif?