QuestionQUESTION: I am trying to install a new deck into my 99 Grand Am. I have read all of the posts and they suggest to use the wiring harness. Well I do not have a wiring harness and am struggling with the duplicate wires and if they should be attached or left or what. There are 2 brown wires and 2 light green wires...etc. I do know what those wires are for as I have a wiring diagram for the car...however for the deck Panasonic CQ-C13334 I do not have the diagram..just the labels on the wires.Leaving me wondering if i should wire both browns together or not...etc.Second problem..there were 4 different wires going to the back speakers and I was told to use the brown/yellow-light and dark blue ones and tape the rest.
ANSWER: Hi Traci,
Duplicate wire colors in a GM radio harness are always going to be different functions. You definitely would not want to combine two wires together; instead, you'll have to determine which wire is the correct one before you make your connection. For example, with your two brown wires, one is a speaker wire and the other may be an illumination wire connected to the parking light circuit. Obviously, if you mix these up and connect the deck's speaker output to the illumination wire, your speaker isn't going to work (and you could easily damage your head unit when you turn your lights on). GM uses green for lots of different functions; one of the green wires is a speaker wire, but the other may be (among other things) a speed sense wire, connected to the vehicle's speedometer circuit. I've seen people mix these up and end up with a speedometer not working.
Your best option is to use a multimeter to verify the wire functions before you start making your connections. For example, to determine if a brown wire is an illumination wire, you'd set the meter for DC volts, put the black probe on chassis ground, connect the red probe to the wire, and turn on your vehicle's parking lights. If you see 12 volts on your meter, you've found an illumination wire.
To identify speaker wires, you'd use the "continuity" function on the meter. If you think you know a speaker wire pair, connect one probe to each wire. If the wires are connected to a working speaker, you should be able to test continuity between the wires (with a resistance reading anywhere between 3 and 8 ohms).
This might not work with the rear speakers, because many Grand Ams are equipped with a factory amp. If you have the Monsoon audio system, you definitely have the amp, and won't be able to test for any speaker wires with a continuity test. Some non-Monsoon vehicles still have an amp for the rear speakers. If yours does, it should be located under the liner on the driver's side of the trunk.
As for the rear speakers, while there are four wires at each speaker, there will only be two wires for each speaker behind the head unit. The extra wires either come from the factory amp, or they're split off with an in-line crossover between the head unit and speakers. Either way, the information you got was correct: you'd only connect to the brown and yellow (left) and dark blue and light blue (right) for the rear speaker connection.
It's very important that you're able to verify each wire's function before you connect your head unit. Failure to do this might result in damage to a vehicle circuit or to your after-market equipment. (This is why it's such a good idea to use a wire harness). If you're not comfortable using a multimeter to test your wires, then I'd strongly suggest taking the car to a professional installer for the wiring.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: OK. So I hooked up the deck without using the light green duplicate wires (to test the other speakers)...all bad news. No power. I thought I had blown the deck, so I went and bought a brand new one. Still no power. I did check all of the fuses under the hood and inside the car, ironically 2 blown...but no power still. I have since bought a new wiring harness to replace the one that was cut off and need to know where i can find the factory wire colors. I thought i had found them..but they did not have the duplicate light green and there is no pink wire in my car.If you can suggest where to look for those specs....and what might have gone wrong with the first deck...because of the power issue...I will be eternally grateful. 3hour speaker swap......4 days of complete car dis-assembly...and soon a complete re-wire...JUST TO BE SURE!lol
AnswerHi Traci,
I don't have a complete listing of all the wires in your car's stereo harness, including the duplicates; but I have a good idea of all the wires that are required for an after-market head unit, and anything else in the harness can be taped off and ignored.
If I were working on your car, I'd be using a digital multimeter to test and verify each wire before I connected it. I can walk you through this process if you have or can get a multimeter. It doesn't have to be an expensive meter at all; it just has to have a DC volts, continuity, and DC resistance features. You should be able to find something for under $20 at just about any hardware store, or Radio Shack. If you're going to be doing any kind of car audio wiring project, a multimeter is essential.
While testing your wires, you'll want to have the door open, and the parking brake set. The first is to stop the "retained accessory power" feature, which can make it harder to find your accessory power wire; the second is to disable the daytime running lights. Keep in mind that your battery might be drained as you're working in the car; you might want to consider hooking up a battery trickle charger during the testing.
Start by cutting all the wires in the radio plug so that they're the same length. Don't cut any two wires at the same time, as this can lead to blown fuses. One at a time, strip each wire and attach a red crimp-on barrel connector. This will allow you to easily test each wire and connect the after-market wires as you go.
The first wire you'll want to find is the chassis ground wire. The factory wire color should be black or black/white; the after-market harness will use a black wire. Set your multimeter for "continuity". To find the ground wire, put the red probe into the barrel connector of the wire you're testing, and touch the black probe to the outer ring of your car's cigarette lighter. (You may have your cigarette lighter disconnected; if so, touch the black probe to the metal bar that runs across the back of your radio cavity). If you're testing the ground wire, you should get a continuity tone from your meter. To double-check, turn on your vehicle's parking lights and test the wire again. If you still get the continuity tone, you've found the ground wire.
Next, look for the constant power wire. This should be orange in the vehicle, and will match with a yellow wire in the adapter harness. Set your multimeter for "DC volts"; if there are different voltage range settings, choose the "20 volt" range. Keep the black probe connected to the dash metal, cigarette lighter ground, or to the ground wire you've already found. Use the red probe to test the wire. If you've found the constant power wire, it should show around 12 volts at all times. (I've never seen this wire in any other color but orange; if it doesn't test, then I'd check the fuse in the passenger-side fuse box).
Now look for the accessory power wire. This wire should be yellow, but I've also seen it as a green wire. Keep the black probe on chassis ground; test the wire with the red probe. If you've found the correct wire, it will show 12 volts with the key in the "ACC" or "ON" positions, and 0 volts in the "off" position. Again, if you can't find a wire with these characteristics, you'll need to check your fuses.
Next, look for illumination wires. You may not need these to connect your new harness, but finding them will keep you from confusing them with other wires. The illumination wire should be dark brown, or brown/white; it matches to an orange wire on the after-market harness. The dimmer wire should be gray, gray/white, or gray/black; it matches to an orange/white wire in the after-market harness. To find the illumination wire, keep the black probe grounded, and use the red probe to test the wire. Switch on the car's parking lights. The illumination wire will show voltage whenever the lights are on. If your wire tests with voltage, move the dash dimmer switch up and down. If the voltage changes, you've found the dimmer wire; if it stays about the same, you've found the illumination wire.
Finally, find all the speaker wires. Your left front speaker wires should be tan (+) and gray (-). Right front wires are light green (+) and dark green (-). Left rear wires are dark brown (+) and yellow (-). Right rear wires are dark blue (+) and light blue (-).
To test for speaker wires, you must have working speakers connected, and cannot have a car equipped with a Monsoon system. (Check under the trunk liner on the left side of the trunk for a Monsoon amplifier; it will be mounted to the side between the back of the wheel well and the tail light). Set your multimeter for "continuity" again. Put one probe in the positive and another in the negative wire of each speaker pair. If you've found the right wires, you should get a continuity tone.
Once you've successfully identified the power, ground, illumination and speaker wires, you can ignore all other wires in the factory radio harness. Just make sure none of them can come into contact with other wires or with dash metal. If you connected barrel connectors to each wire, you can just leave them like that, but make sure the connectors are crimped on firmly and won't come off.
If you find a Monsoon amplifier, and/or have problems identifying speaker wires with your meter, let me know. This might require you to take the car to a professional; but if you're comfortable with the multimeter, I might still be able to help you do it yourself.
By the way, a pink wire is usually only found in vehicles with the Monsoon system, or with a separate cassette or CD module.
Hope this helps!
Brian
