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dc-dc? Big n00b needs some info. (FM-Mod)

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  • dc-dc? Big n00b needs some info. (FM-Mod)

    ok, i am fine with computers and general audio stuff, but i have absolutly no experience with car audio except pluggin a diskman into a tape adapter with a lighter plug. That said i think my problem is a simple one so hopefully someone hear can help. I dont mind being made to feel stupid if it solves this. so flame away

    All i want to do is hook up an FM Modulator (Innovateck FM-02) I have never wired anything by myself in a car and it doesnt have any sort of plug, just two wires (red = -12vDC & black = ground)
    i just wanted to test it so i pulled the clip off of the back of the lighter plug and stuck the wires in there... nothing... i know power is going through it (tested with the multimeter on both ends) do that isnt the problem...

    so i dunno... is the wire on the lighter not a 12vdc? isnt that what everyhting in a car is... please help me, im retarded.


    P.S. i searched alot, aprently no one else is dumb enough to mess up this simple of an operation.

  • #2
    Dumb question, but was the car on? Sometimes the cigarette socket is switched so it's only on when the key is in the accessory position or the car is on... Just covering the bases...
    mATX mobo
    2.4 GHz Celeron (prescott)
    512 MB RAM
    80 GB 3.5" HD
    Runnin off an inverter (for now)
    7" Lilliput
    Microsoft (Pharos) USB GPS
    Have yet to pull the trigger on a slim slot load DVD
    STATUS: who knows... I don't


    • #3

      yea, thankfully i managed to figure that one out on my own so im not a total loss

      i actually tried it through the power that goes to the light bulb in the ash tray as well which only runs when the lights are on... same deal

      im thinking the unit might just be bad...

      is there a dif between "-12v" and "12v"

      cause the wire says "-12v"

      thanks for the quick reply by the way!


      • #4
        Originally posted by lupos
        is there a dif between "-12v" and "12v"
        Yes, there is: +12V, -12V, and GROUND are three different things. At the moment, I can't tell you what the differences are, because I'm drunk.


        • #5
          -12 means you have the two wires backwards. Your Positive probe is touching the negitively charged wire and the neg probe is touching the positively charged wire. Ground is the absense of voltage. Though there are several types of grounds, basically it is the part with the LARGEST votage difference, usually, perferably the other terminal / power line. 12v means that you have 12v.


          • #6
            Oh yeah, second thought, -12v also can be ground depending.. Hope this confuses you more. =p


            • #7
              more confused...

              yea you succeeded!
              i am confused as hell... see the thing is the two wires are labeled -12v and GND (ground i assume, i think i got that much).

              so i guess the question is then... if i have a -12v wire and a gnd wire... what the heck do i plug them into? what if i was just hooking them straigh to the battery to test it... woudl i put one on the negative and one on the engine block?

              this is the one.


              • #8
                just forget about - in front of 12V sign and connect it to your positive 12V. There are no cars that would have +12V, GND AND -12V voltages. So the red wire: + 12V. Black one: Ground. By saying "ground" I mean any metalic part of the chassis of your car as it should be directly connected to (-) pole of your battery by design. Of cource, no part of your car is "grounded" meaning electrically connected to mother earth.

                Since the modulator is fused (the white block on your red cable, you can connect both wires directly to your battery: red one to (+) sign pole, the black one to (-) sign pole.
                Just one advice: place the FM modulator as far from the engine as possible.


                • #9
                  you could of just run the power from the head unit.. that is 12v..(red cable or red with green)