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12v rocker works; 12v rocker with ground...does not

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  • 12v rocker works; 12v rocker with ground...does not

    Good Evening,
    I finally found someone to make me a custom switch panel for my mustang's center console. Prior to this, I had loose wires with standard 2 prong 12v rockers(no ground prong, no LED).

    Along with the panel, the vendor sent me 12v rockers that include a 3rd ground prong which activates an LED.

    The computer works fine with the old switch.
    The computer works fine with the new switch if the GROUND IS DISCONNECTED
    If I connect the ground to the switch, the computer WILL NOT turn on...(The LED does function though)

    Any ideas as to why the ground might be messing up my situation?

    Here is a link to my current setup for power, etc.
    Over a year later I guess it's true...a carPC is NEVER complete

    2002 Mustang CarPC

  • #2
    Where are you grounding the switch to?

    Comment


    • #3
      Which prong are you grounding? It sounds to me like you have the switch wired incorrectly.
      1999 Mercury Grand Marquis GS with: ASRock E350M1 w/4GB RAM, 80GB Intel SSD, Opus DCX3.120, Visteon HD Radio + HDR-USB, PL-18N wifi, OBDLink Scan Tool, BTA6210 BT, BU-353, Win 7 Ultimate, CF 4.0, Alpine MRP-F240 + MRP-T220, RF Punch 1572s, Kicker 8" Comp.

      Comment


      • #4
        Prong 1 is connected to my ignition/accessory
        Prong 2 is connected to the pc
        Prong 3(Gold) is connected to a metal bolt(connected to the body) beneath my center console

        Thanks a million for the replies. Hopefully I can figure this out(not a HUGE deal...but annoying after I spent the $ for a quality looking item)
        Over a year later I guess it's true...a carPC is NEVER complete

        2002 Mustang CarPC

        Comment


        • #5
          The rockers in the pic you posted on your usb thread are the same ones I have. There should be no problem with that switch. Pin 1 is the ground, pin 2 is the out to your pc, and pin 3 is the input from your 12v power source. Looks like the pin is wired backwards. You can test the connections using a multi-meter. Or, if you don't have one, use a 9v battery and some wire and a flashlight lightbulb to make a circuit.
          Last edited by kegobeer; 09-15-2011, 06:01 PM.
          1999 Mercury Grand Marquis GS with: ASRock E350M1 w/4GB RAM, 80GB Intel SSD, Opus DCX3.120, Visteon HD Radio + HDR-USB, PL-18N wifi, OBDLink Scan Tool, BTA6210 BT, BU-353, Win 7 Ultimate, CF 4.0, Alpine MRP-F240 + MRP-T220, RF Punch 1572s, Kicker 8" Comp.

          Comment


          • #6
            Thanks for the reply. When I stated PIN numbers I didn't refer to the actual switch. This is the switch I have from this actual company. I called the representative yesterday before posting and he had said everything sounded fine and was confused as to why it wouldn't work. I even tried one of the other 2 switches I ordered and i have the same issue.

            How would I test with a muli-meter(Which I do have)? Should I see if the output to the PC is lost when the ground is connected?

            I really appreciate the help.
            Over a year later I guess it's true...a carPC is NEVER complete

            2002 Mustang CarPC

            Comment


            • #7
              yes, testing with the multimeter would be a very good idea.
              My OLD 2001 Mitsubishi Eclipse GT:
              "The Project That Never Ended, until it did"


              next project? subaru brz
              carpc undecided

              Comment


              • #8
                That is the same switch sold at Autozone and O'Reilly Auto Parts. Connect one lead to pin #3 and the other to pin 2. Turn the meter to ohms. When the switch is closed (the side with the LED pushed down) the meter will read very close to 0 ohms. When the switch is open, the meter will not read any ohms.

                I still think the switch isn't wired correctly - it sounds like you have the ground pin connected to your 12V source, instead of it being connected to the 12V input pin on the switch.
                Attached Files
                1999 Mercury Grand Marquis GS with: ASRock E350M1 w/4GB RAM, 80GB Intel SSD, Opus DCX3.120, Visteon HD Radio + HDR-USB, PL-18N wifi, OBDLink Scan Tool, BTA6210 BT, BU-353, Win 7 Ultimate, CF 4.0, Alpine MRP-F240 + MRP-T220, RF Punch 1572s, Kicker 8" Comp.

                Comment


                • #9
                  Forgive me - just dropping in and very subject to brain farts... (What a night!)


                  As I see it, the switch is wired ok.

                  If +12V & GND were interchanged, the LED would not light when ON (unless it is bridge rectified which they don't normally do - those switches are maked +12V etc, not pwr in & pwr out and opposite power polarity or equivalent.
                  If +12V & the output were not connected across the switch contacts, the pc would not turn on.
                  If +12V & GND were across the switch contacts, it would melt/blow (ON shorts +12V to GND).

                  Ergo, the switch is wired fine. But please check/confirm my logic...!


                  The PC works with no GND connected - as if the 20mA LED is somehow effecting the connection. (Restating the obvious.)

                  Check output with a reasonable load - maybe a light bulb (brake bulb ~21W => ~2A, headlight 60W = 5A etc; a dash globe ~3W = 250mA may be a bit low to detect a high switch impedance - not that a GND via a LED sould impact that). A multimeter alone won't detect the ability to suppply high current (it only draws uA).


                  The "always connected to PC" LED (20mA) grounds the PC +12V, but that has no effect - ie, it is +12V when the LED s on (unless a faulty (high-impedance) switch), and it's not keeping the PC on when OFF - that is sometines an issue when LEDs etc are connected in OTHER sitations, but not in this case.



                  A solution may be to have the switch energise a relay that powers the PC. Though I'd still want to know ytf the 10A reated switch itself doesn't work, I'd normally wire it that way because I'd use a direct feed via a fuse from the battery (as done by most - it's the cleanest power supply) AND I dislike running more than a few Amps through a switch - even 16A rated switches. (I can expand on that if required.)
                  In this case I'd just check that the relay coil gets 12V and not something like 8V which can be close to its drop-out voltage.


                  I'll check in again after brekky & coffee....
                  Last edited by OldSpark; 09-16-2011, 09:09 PM.

                  Comment


                  • #10
                    i should add that i have 5 of those switches installed in my car, as well as a green, yellow, and blue led version, and none of mine have any problems.(the green switch is connected in the exact same fashion as yours)
                    My OLD 2001 Mitsubishi Eclipse GT:
                    "The Project That Never Ended, until it did"


                    next project? subaru brz
                    carpc undecided

                    Comment


                    • #11
                      I am assuming that the 12v from your switch goes to the ign wire on your intelligent automotive power supply. I'm also assuming that you've wired your automotive power supply correctly, connecting the 12v input to your distribution block and connecting the ground to your chassis ground.
                      1999 Mercury Grand Marquis GS with: ASRock E350M1 w/4GB RAM, 80GB Intel SSD, Opus DCX3.120, Visteon HD Radio + HDR-USB, PL-18N wifi, OBDLink Scan Tool, BTA6210 BT, BU-353, Win 7 Ultimate, CF 4.0, Alpine MRP-F240 + MRP-T220, RF Punch 1572s, Kicker 8" Comp.

                      Comment


                      • #12
                        Thanks for that confirmation soundman.

                        I'm a bit more awake now, but it still perplexes me.
                        How can a LED prevent power on?
                        And if the load current was too high for the switch, it wouldn't power up without the LED.
                        AHA - there we have it - the 20mA LED is enough to overload the 10A switch and hence.... (No - I won't say "now way", but that is essentially ridiculous; a switch instantaneously failing with an additional 0.2% (over)load.. no way!)

                        And yes, Archy tried the other switches. So we have ruled out the switches (unless it's a weird batch fault!) and the connection topology, and connections.

                        I'm gonna love the solution to this one - especially if it's another one of my Do'hs! that is so obvious. (See if I re-quote my last reply's first line - damned woosy oldfart!)

                        Comment


                        • #13
                          ^ it shouldn't overload the switch, as he is only using it to trigger the power supply(the ACC wire input), not cut the main feed.

                          i haven't taken one apart, though many of these devices are built the same-- they are almost too simple to mess with outside devices-- it is only a small 1/8w resistor in series with a small led. there is not enough room inside for a pcb to allow for voltage regulation or any complex operations....

                          i found a pic:



                          it looks like it is connected correctly, and is connected exactly the same as my switches(note-- he did say that he connected the gold pin to ground)
                          My OLD 2001 Mitsubishi Eclipse GT:
                          "The Project That Never Ended, until it did"


                          next project? subaru brz
                          carpc undecided

                          Comment


                          • #14
                            Originally posted by OldSpark View Post
                            The PC works with no GND connected - as if the 20mA LED is somehow effecting the connection. (Restating the obvious.)

                            Check output with a reasonable load - maybe a light bulb (brake bulb ~21W => ~2A, headlight 60W = 5A etc; a dash globe ~3W = 250mA may be a bit low to detect a high switch impedance - not that a GND via a LED sould impact that). A multimeter alone won't detect the ability to suppply high current (it only draws uA).


                            The "always connected to PC" LED (20mA) grounds the PC +12V, but that has no effect - ie, it is +12V when the LED s on (unless a faulty (high-impedance) switch), and it's not keeping the PC on when OFF - that is sometines an issue when LEDs etc are connected in OTHER sitations, but not in this case.



                            A solution may be to have the switch energise a relay that powers the PC. Though I'd still want to know ytf the 10A reated switch itself doesn't work, I'd normally wire it that way because I'd use a direct feed via a fuse from the battery (as done by most - it's the cleanest power supply) AND I dislike running more than a few Amps through a switch - even 16A rated switches. (I can expand on that if required.)
                            In this case I'd just check that the relay coil gets 12V and not something like 8V which can be close to its drop-out voltage.
                            Your obvious statement is definitely true. Somehow it seems as if the LED is making a difference...and/or the ground.

                            Not to show my lack of electrical knowledge, but how would I use the switch to power a light bulb? Obviously the bulb would touch/be wired to the center prong(where the PC would be). What would I use to power it? Will the 12v from a fused accessory line be enough to power it?

                            How would I add a relay to this setup? I'm not sure if I am committed to that much of a task, but it is worth asking. As of right now, the switch works albeit minus the LED lol.
                            Over a year later I guess it's true...a carPC is NEVER complete

                            2002 Mustang CarPC

                            Comment


                            • #15
                              Originally posted by kegobeer View Post
                              I am assuming that the 12v from your switch goes to the ign wire on your intelligent automotive power supply. I'm also assuming that you've wired your automotive power supply correctly, connecting the 12v input to your distribution block and connecting the ground to your chassis ground.
                              Correct. I have an OPUS 360 power supply(Probably overkill, but whatever lol). I had that previous 12v rocker(MINUS LED/GROUND) that worked fine for over a year, so I can only assume it was wired correctly in the same fashion that you list.

                              Originally posted by OldSpark View Post
                              Thanks for that confirmation soundman.

                              I'm a bit more awake now, but it still perplexes me.
                              How can a LED prevent power on?
                              And if the load current was too high for the switch, it wouldn't power up without the LED.
                              AHA - there we have it - the 20mA LED is enough to overload the 10A switch and hence.... (No - I won't say "now way", but that is essentially ridiculous; a switch instantaneously failing with an additional 0.2% (over)load.. no way!)

                              And yes, Archy tried the other switches. So we have ruled out the switches (unless it's a weird batch fault!) and the connection topology, and connections.

                              I'm gonna love the solution to this one - especially if it's another one of my Do'hs! that is so obvious. (See if I re-quote my last reply's first line - damned woosy oldfart!)
                              If you think of anything to try...please let me know lol.



                              Originally posted by soundman98 View Post
                              ^ it shouldn't overload the switch, as he is only using it to trigger the power supply(the ACC wire input), not cut the main feed.

                              i haven't taken one apart, though many of these devices are built the same-- they are almost too simple to mess with outside devices-- it is only a small 1/8w resistor in series with a small led. there is not enough room inside for a pcb to allow for voltage regulation or any complex operations....

                              i found a pic:



                              it looks like it is connected correctly, and is connected exactly the same as my switches(note-- he did say that he connected the gold pin to ground)
                              Yes, that is pretty much what my switch looks like. The left prong is the fused accessory line, the center goes to the OPUS 360...so this is more of a signal wire vs power feed.



                              On a side note, I tested ohms with the multi-meter. According to the fancy machine, the switch is hooked up correctly.


                              I really appreciate you guys taking so much time to help with this. You all have far more knowledge than I, and I truly appreciate it.
                              Over a year later I guess it's true...a carPC is NEVER complete

                              2002 Mustang CarPC

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