QuestionQUESTION: I'm trying to put in an aftermarket head unit into my car and me and my friends had thought we had found a wiring diagram online that would allow us to cut 32 pin connector from the car and then just hardwire the head in. The diagram we found apparently wasn't correct because we can't get the unit to even power on. So can you please help me by telling me what wires need to go where or if I've totally messed everything up by cutting that connector out.
ANSWER: Hi Bryce,
I'm not sure what diagram you're using, or where you're making your wire connections; but you should know that even the ribbon-cable connector in the LeSabre doesn't include all the connections you'd need for an after-market head unit. The factory radio in the LeSabre is activated by the vehicle's data bus system, instead of using a key-switched power wire like an after-market deck. That means that you either need to find a key-switched power source for the red "accessory" power wire, or connect it to a constant power source along with the yellow wire. If you combine the red and yellow wires to a constant power source, you'll have to remember to turn the deck off every time you turn the car off, or you'll drain your battery.
If I'm installing a new deck in one of these cars, I'll either use a special adapter module made to fit the ribbon cable connector and work with the vehicle's data bus system, or I'll use a Scosche GM07B harness to fit the stock connector, and route the accessory power wire to another power source. Finding a key-switched power source is easier said than done in this car. My favorite trick is to tap into the RAP relay, located in the fuse box under the rear seat; but this relay isn't equipped in all models.
If the factory radio connector is still attached (even if it's no longer mounted to the rear wall of the radio cavity) I'd strongly suggest buying the adapter module. Not only will this provide the accessory power connection you need, it will also let you retain the factory warning chime feature that would otherwise be lost when you remove the stock head unit. The part you need is either a Metra GMOS-05 (if you have Onstar) or a GMRC-04 (if you don't have Onstar, or don't want to keep it working).
If you aren't interested in buying the module, then your biggest challenge will be finding the accessory power source. To make your deck work, you need constant power, accessory power, and ground. The ground can be connected to any handy body metal, and the constant power connection can be found right at the battery or rear fuse box, if necessary. The accessory power connection is always the tough one; if there's no RAP relay or switched power source at the rear fuse box, you might be able to tap the brown wire at the ignition switch. This is a low-current power source, though, so I usually avoid it; overloading the ignition switch could make it impossible to start the car.
Good luck!
Brian
---------- FOLLOW-UP ----------
QUESTION: Thanks Brian unfortunately we've already cut the factory adapter out of the car leaving us with twenty wires. Now the pioneer head unit that I bought only has twelve wires for it's adapter so we're left with eight wires that we don't know where to hook up. We're fairly certain we have all the speakers hooked up right but we can't get the unit to even turn on. I'm guessing this must be because of what you said with the yellow and red wire. We spent a good half our testing combination's of colored wires left after hooking up the speaker wires but the unit would never power on. I'd purchase a wiring harness for it but I was wanting to get this done in a weekend so I wouldn't have to have my dashboard all ripped out. Unfortunately that hasn't gone so well so now I'm hoping you can help me figure out what all wires need to be hooked up where so that I don't have to take this to a professional and drop another 100 bucks in order to have everything installed.
AnswerHi Bryce,
My information only shows 18 wires in the factory plug, so I won't be able to clear things up completely; but many of the wires aren't required for the after-market head unit, and others have duplicate functions. You should make sure that any wires that aren't connected to the new deck are individually insulated and wrapped up so there's no chance they can be pinched behind the head unit. This is especially true of the violet wires; these carry data signals, and a problem here can cause trouble with all sorts of vehicle systems.
If you cut through more than one wire at a time when cutting off the factory plug, it's very likely that you have a blown fuse. Check the audio fuse, in position 21 in the fuse box under the rear seat. This should supply constant power to the radio harness.
You should have:
-3 violet wires
-3 black wires
-2 orange wires
-2 yellow wires
-1 white wire
-1 tan wire
-1 gray wire
-1 light green wire
-1 dark green wire
-1 dark brown wire
-1 dark blue wire
-1 light blue wire
My advice is to use a digital multimeter, and verify each wire's function before you connect it.
The three black wires should all be chassis ground. Confirm this by setting the meter for "continuity test". Touch one probe to the outside ring of your cigarette lighter socket, and use the other probe to test each black wire (one at a time). Each one should show continuity, with very low resistance, with the cigarette lighter ground. If the wires test correctly, combine them all together and connect them to the black wire from your head unit.
The two orange wires should be the constant power source. Set the meter for DC volts, and touch the black probe to the cigarette lighter shield. Test the wires with the red probe. You should get a reading around 12 volts for each orange wire. If they test correctly, combine them together and connect them to the yellow wire from your head unit. If they don't test, you may need to check the Audio fuse again.
One of the yellow wires is an illumination wire; the other is a speaker wire. It's important that you don't mix them up. To find the illumination wire, turn on your parking lights and set your "dimmer" switch to maximum brightness. Set the meter for DC volts and touch the black probe to the cigarette lighter ground. Test each yellow wire with the red probe. The illumination wire should show voltage with the lights on, no voltage with the lights off. If your new head unit has an orange or orange/white wire, it should be connected to the yellow illumination wire.
The white wire is an activation wire for the vehicle's built-in antenna amplifier. This should be connected to the blue or blue/white wire from your head unit. If you don't connect this wire, your radio reception may be poor. There's no practical way to test this wire without the factory head unit connected, although you might be able to find the antenna amplifier (under the rear headliner) and look for the same wire there.
Your speaker wire colors should be as follows:
Front left: tan (+) and gray (-)
Front right: light green (+) and dark green (-)
Rear left: dark brown (+) and yellow (-)
Rear right: dark blue (+) and light blue (-)
To verify speaker wires, set your multimeter for "continuity" or "resistance". Touch one probe to each wire in a pair. You should get continuity between the two wires, with a resistance reading between about 4 and 8 ohms.
This just leaves the red wire. Here are a few ideas for that one:
Pull off the knee panel under the steering column. On the right side of the opening, you should see a 3-pin plug, with at least one orange and one black wire. This is the power harness for your cigarette lighter. Now, in some models, the cigarette lighter is set to switch off about ten minutes after the key is turned off. Cycle your key in the ignition, then use the multimeter to test the voltage in the orange wire. You should get 12 volts. Take the key out, close the door, and wait about 10-15 minutes. Test the wire again. If you get 0 volts this time, then you can connect your deck's red wire to this orange wire. The new radio will stay on after you turn the key off and get out, but it should shut off in ten minutes, so it's an acceptable substitute for a key-switched power wire. (If the wire doesn't lose voltage after 10 minutes, take a look at the cigarette lighter fuse in the engine compartment fuse box. It may be designed so that it can be placed in two different positions. Try moving it to the other position, and test the wire again).
Another possibility is the RAP relay, in the fuse box under the rear seat. If it's present, you can pull it out, connect your wire to one of the terminals, and place it back in again. Then you can extend the wire up to the front for the head unit's accessory power connection. The terminal you need is either #30 or #87; you'll have to test them to see which is correct. One terminal will show voltage at all times; the other terminal will switch on and off as you turn the key to ACC and back (assuming the driver's door is open). If you connect your accessory wire to the switched power terminal, your new radio will work similarly to the factory radio--it will stay on after you switch the key off, until you open a door. This is ideal. If you do connect your power wire here, it's very important that you make a clean, tight connection, with no loose wire strands to touch the other relay terminals. I'd also put a fuse on your wire within a few inches of the relay connection, so that if your wire gets shorted, it doesn't harm a vehicle circuit. A 3-amp fuse should be fine.
Hope this helps!
Brian
