Power supply behind HU...which wire?

I need power for an antenna booster I am going to use. It plugged right in but I need to power it from somewhere. Which wire do I use?

I was told to use the gray wire but there are two gray wires. One is a thin wire on the side with the volume knob. The other is a thicker wire that is wrapped in tape and is on the right side (when looking down - the tuner knob).

Any advice on how to splice into it (what to use)? I am not experienced with wires and know nothing about soldering. Whats the easiest way to cut and splice the wires?

Thanks.

 

You should use these: http://www.radioshack.com/product/i...odsPerPage=60&retainProdsInSession=1&y=7&x=10

No cutting needed. You could use a mulitmeter with a pointed tip to check which wire is hot when the truck ignition is on.

 

Ok, so no diagrams out there to tell me which wire to splice from?

I have 2 testers but I don't know how to use them. Do I have to ground the black? Where do I ground it to? Can I use the metal around the DC outlet? The red point gets stuck into the harness, right?

I'll take some pictures of my multimeter and maybe someone can advice what setting to use to test (it has a bunch).


Though it would be best if someone would just tell me which wire it is!!!!

 

crap, I just tapped the switched 12v wire. It's on the plug that is on the volume know side.

I am thinking it was the one next to the end. The end wire is constant 12v, the next one is switched...I wasn't paying attention to the color since I was looking at the meter. For sure it was one of the two though. It's in the plug with the smaller wires, not the thick ones.


On your meter, put the dial to VDC on the 20 range. Ensure your meter leads are in the correct spots. The red one will need to be in the V not the ohm jack. Black one will always be in the ground. You put the black lead to a good ground (any bare bolt head will work), and then check the pins on the wire harness from the radio. Check with ignition off first. You'll have one wire that has 12v or more on it, rest dead. Turn on ignition, you'll have an additional wire with 12v or more on it. That additional wire is your switched source. Tap that wire. The more I think about it, it's the second wire from the left in the upper row when looking at the plug.

 

Thanks GoBlue...here are some pictures of what I have going on:

The volume side is on the bottom of the picture.




The multimeter that I have no idea how to use!


A more simple one that I use for basic stuff

 

It's the brown wire next to the grey one. Both are 12v wires, just one is constant hot and the other is switched 12v.


ok, now with the meter, put your dial to the black 50 (about the 1 oclock postition). You will be reading the middle row of numbers on the scale (0, 10, 20, 30, 40, 50). This means you are on the 50 V scale and your needle should move inbetween the 10-20 indicating 12-14 volts when you find a 12v source.
Put your black lead on a good ground like a raw bolt/screw head. The red lead just probe the pin in the connector. Your needle should deflect with 12v present, nothing if it's dead. Turn the key and probe the other pin to see if you now have two hot wires. The one that is dead with the key off, that is your switched hot wire.

 

There is no brown wire?

On the top row of that harness, there is green, blank, blank, gray, purple and blue.
On the bottom row there is light blue, pink, light green.

 

light blue and the one next to it, what ever color it is. Looks brown on my monitor

 

So what happened?

 

I'm getting NOTHING from either multimeter. I am touching the red to the connection inside the harness and the black to an unpainted screw.

Would the screws that are on the radio itself be grounded? I can't reach any other screws. I did try to ground it to the metal surrounding the DC outlet (cigarette lighter). I tried all the wires and go no response, so I am apparently doing something wrong.

I am headed over to a friends house today to see if he can get some kind of reading from the wires.

Even more frustrating, as I was checking the wires, the radio was hanging there. When I put it back in, I realized it was scratching up the dash under the air controls. Damn dash scratches so easy! All this because my radio gets shit for reception. First vehicle out of the 7 I have owned that had this problem. I should just go aftermarket!

 

might be having meter malfunction. The meter is turned ON correct? Battery good in tehe meter? When you go to the OHM setting (green area), and touch the leads together...what happens? Your needle should deflect indicating a short (which it is since you are touching the two leads together). You could also check the meter by checking your battery voltage under the hood. If you get a good response from the meter there, then you are doing something wrong inside the cab. If no reponse, it's the meter.

 

Ok...I guess I should've verified the meter worked when I started using it

Just went outside to test it and got NOTHING. It has a fresh battery and I touched it directly to the terminals on my battery. I also get no reading when shorted on the OHM setting. It does not have an on/off.

I'm off to the store to get another one. I'll let you know.

 

when testing the truck battery, you did have it on the black 50v position (1 oclock)?

 

At one point, yes. I actually tried every setting (10, 50, 250 and 500).

 

ok cool. Just trying to eliminate the silly stuff we all do once in a while.

 

Got it! Using an accurate multimeter, I determined the light green is constant power and the light gray is switched power. I connected to the switched power supply using a blue quick connect and it works as I had hoped!

Radio reception is much stronger. Worth the effort but I'm still a bit peeved about the scratches in my dash. Oh well...


GoBlue...thanks a ton for the help! Hope I can repay it someday.

 

Glad you got it sorted out and learned something in the process. That's what this hobby is all about.