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jkfeagle
09-26-2007, 07:41 PM
The other day I got into my car and started it up. Noticed the radio was quite loud so went to turn it down and as soon as I touched the volume button the radio died. I checked the fuse both on the radio and in the car and both were OK so I assumed the radio had bit the dust. I just got a new radio and installed it and the radio won't come on...i.e. no power. Where else do I need to look?

John

dB-SPL
09-26-2007, 07:43 PM
Possibly something shorted?

-Bill-

jkfeagle
09-26-2007, 07:46 PM
So where do I need to check?

dB-SPL
09-26-2007, 07:55 PM
+12V and Ground wires.

-Bill-

fwb_1234
09-26-2007, 07:56 PM
and the switched wire (red)

azbass
09-26-2007, 07:58 PM
unless you do a continuity check on teh fuse using a DMM don't assume the fuses are ok.

jkfeagle
09-26-2007, 08:06 PM
I changed the fuse in the fuse box to no avail on the off chance it was bad. So I need to check the red, yellow and black wires. How do you check to see if the wires are OK on a car? Just FYI, the radio wires are sodered to a harness that plugs into a harness in the car.

jkfeagle
09-26-2007, 09:10 PM
OK. I know that sounded like a bonehead question. I'm used to testing AC circuits. Do I need to test the 12V with one lead of the DMM and the other to ground? What about the switch wire?

fwb_1234
09-27-2007, 01:13 AM
OK. I know that sounded like a bonehead question. I'm used to testing AC circuits. Do I need to test the 12V with one lead of the DMM and the other to ground? What about the switch wire?

Yes, by the way this is DC; don't forget.

The yellow-black should be 12v all the time, no matter how the car is on. Red should be 0v with the car off and 12v with the car on.

jkfeagle
09-27-2007, 07:32 PM
Here is something bizarre. The yellow wire coming from the car is the switched wire, power to it when the ignition is on. The wire is red coming from the harness that plugs into it going to the radio though. The 12V wire (which I assume is the thicker red wire coming from the car) is showing 0V all the time. Where to from here?

Atimm693
09-27-2007, 09:50 PM
Id replace the fuse under the hood, even if it doesnt look blown it still might have gone bad.

jkfeagle
09-27-2007, 10:00 PM
I'm not sure what fuse you're referring to. The low voltage fuses are under the dash in my car and I've swapped the two going to the radio out already even though neither looked blown. The only fuses under my hood that I'm aware of are the high voltage ones and none of those goes to my radio. Am I missing something here?

jkfeagle
09-27-2007, 10:10 PM
Would the wire run straight to the fusebox from the radio? Is the only option left replacing the wire? Ugh!! Please tell me there's another way!

Ferendon
10-10-2007, 12:24 AM
Check ALL fuses. There are quite a few fuses that are not directly related to a failed system, that can be cause the problem. I.E. a fuse for an SJB or BCM failing, causing the locks to stop working, whereas the locks have their own fuse, that is perfectly fine. Never assume that the "thicker red wire" is a +12v.
Directechs.com, password is password, click on Directwire, pull up your car, choose Audio, and click 'Select'. That will give you the wire colors for the vehicle.

On the radio side of the harness, Yellow should be +12v constantly, red will change with the ignition, and black is a constant ground.
http://www.the12volt.com/request/request2.asp <--- Standard pin-out for head unit harnesses.