I recently ordered a new head unit from Crutchfield and thought I'd share the wiring instructions and my own observations for installation.
When you order through Crutchfield, most units come with a free wiring harness, antenna adapter, radio removal tools, instructions and lifetime customer support. Shipping was also free. These are great bonuses that made me feel like ordering my unit at retail was worth it vs. saving a few bucks and going used or amazon.
When I received my package, I wasn't exactly sure how to wire everything up but it's very simple. As background, my car is a 00 S with the hifi stereo option. This means I have dash speakers, door speakers, rear shelf speakers and a 6 channel amp. When ordering, I wasn't sure why their options didn't include anything for a 6 channel config, but it does work. I selected "without navi, with door speakers". Your application may vary.
After unpacking everything, you will have 2 wiring harnesses (one black, one red with RCAs), antenna adapter, radio removal tools and your radio.
1st, plug the antenna adapter into the antenna port in the back of the new deck.
2nd: Wiring.
Your new deck will have wires sticking out the back and RCA plugs. You'll need to connect a few of these wires to the black harness.
BLACK HARNESS:
Yellow (switched power): Connect this to the ignition line on your new deck
Red (12V Constant): Connect this to the constant power on your new deck
Black (ground): Connect this to the ground wire on your new deck
Orange (illumination): optional. My deck didn't have a cable for this.
The rest of the wires on the black harness are for cars that don't have an OEM amp. Leave them alone/tie them back out of the way. I think I zip-tied the rest in a bunch.
RED HARNESS:
These RCA cables will connect to the back of your new deck. If you only have 4 pre-amps, perfect. If you have more (mine has 6 for future upgradability) you'll only use the Front and Rear RCA outputs; the subwoofer outputs will be left alone for now.
Gray RCA: connect this to the new deck, front right
White RCA: connect this to the new deck, front left
Green RCA: connect this to the new deck, rear left
Purple RCA: connect this to the new deck, rear right
blue/white wire: this is for the amp turn on and is also connected to the yellow wire from the black harness.
That's it! So far you've crimped 4 wires together and plugged in 4 RCA cables...piece of cake.
Before working on the car, some people say to disconnect the negative terminal from your battery. I didn't, but I did unplug the radio fuse in the fuse panel (much easier). Please make sure you have your Becker's radio code before starting in case you stop and have to use the stock radio for any reason.
Use the radio removal keys they supplied to take out the Becker. The teeth face inward and you'll want to use the stubby pointed ends, not the long pointed ends. Stick them in till you feel them click and pull out. When you pull the radio out, you'll notice blue tabs where the keys are stuck in. Press them in to release the keys.
Unclip the black harness and yellow harness from your Becker. Also unclip the radio antenna. The Becker should now be free.
Slide it out and store it.
Look into the radio recess and on the left side, you'll see a wire that's hooked onto the car's radio cage/chassis. Unclip this wire and tape the end. This wire is part of your car's radio anti theft deterrent. When the radio slides out, it breaks the ground and the car knows the radio has been removed. You'll get the horn toot when you lock your car (same as if you leave your armrest, door or trunk open) if you leave this plugged in.
I chose not to install the supplied new radio cage but I may go back and install it now that I've tested the radio out. They make the cages hard to take out once you put them in. If you choose to do so, you'll want to do that now and route the wires through the back.
You're now looking at the harness Crutchfield supplied and your OEM harness coming out of the car and saying to yourself, these are different sizes. They look different, but they do fit. The car's black harness will go in the Crutchfield black harness and the car's yellow harness will go in the Crutchfield red harness. Look at the pin orientation and you'll see how it fits.
Plug in both harnesses, plug in the antenna and test your system. If all went well, you should have a deck that works with all speakers going.
Tuck everything back, slide the new radio in and enjoy.
