One of the first projects many new 911 owners perform on their car is to remove and replace their stereo head unit. I know that if I buy a car that has a weak stereo, it's one of the first things to go. The factory Porsche head units (manufactured by Becker) are best described as barely adequate--the technology is at least 10 years old in most cases, and the controls on the units are beyond terrible. This article specifically contains only wiring information for the 1999-2004 Carreras, but is also applicable to the 2005 and later cars.
The good news is that the replacement process is relatively easy, providing you have the right information and the right parts. First, disconnect the battery (see Pelican Technical Article: Porsche 911 Carrera Battery Replacement Trickle Charger Installation). The radio harness has constant voltage supplied to it, and you don't want to accidentally blow any fuses or damage any electrical components. Using the set of factory radio removal tools (available from Becker, part number BNA-1184-989), pull out the radio as detailed in Figure 2. On the back of the unit, there may be a few wire connectors and a smaller antenna connector. Remove the antenna connector by simply tugging on it.
In order to install your new radio, you will need some cable adapters for the Carrera's wiring harness. The adapters plug into the factory connectors and have leads on them that you can then connect to the leads or connector on your new radio. You can cut the OEM connector off and tap directly into the factory harness, but I strongly caution against this--it's best to use the adapter cables (cost about $20). I put some spade connectors on the ends of the harness adapter and the connector that plugged into my new radio. The kits I used for my 2000 Porsche were Metra brand, PN: 70-1787 (VW/Bose AMP Integration), and the Euro antenna adapter kit from Scosche, PN: VWA-KB (Volkswagen Antenna Adapter Kit). This antenna adapter kit contains two adapters so that you can use an aftermarket stereo and/or install an in-line FM modulator iPod interface (see below). These kit part numbers should be good for all of the Carreras through 2004. For 2005 and up models, check the radio you have in your car before you order the adapters.
In general, the most difficult part of installing a new radio is figuring out how to wire it. I've done all of the legwork for you here by putting together this handy wiring chart (1998-2004). The green connector and blue connector on the back of the radio are for the operation of the CD changer, if your car has one (mounted in the front trunk, see 101Projects.com website for pinouts on those connectors).
|Color||Purpose||Connector and Pin|
|Grey/Pink||Speed dependent vol control||Black Connector A: Pin 1|
|Unused||Black Connector A: Pin 2|
|Yellow/Black||Mute for telecom interface||Black Connector A: Pin 3|
|Red/Black (thick)||Constant power 12v (Fuse D8)||Black Connector A: Pin 4|
|White||Power antenna control||Black Connector A: Pin 5|
|Grey/Blue||Illumination (headlamps on)||Black Connector A: Pin 6|
|Orange||12 volt switched power (Fuse E1)||Black Connector A: Pin 7|
|Brown (thick)||Chassis ground||Black Connector A: Pin 8|
|Green||Right rear speaker (positive)||Brown Connector B: Pin 1|
|Green/Black||Right rear speaker (negative)||Brown Connector B: Pin 2|
|Red||Right front speaker (positive)||Brown Connector B: Pin 3|
|Red/Brown||Right front speaker (negative)||Brown Connector B: Pin 4|
|Yellow||Left front speaker (positive)||Brown Connector B: Pin 5|
|Yellow/Brown||Left front speaker (negative)||Brown Connector B: Pin 6|
|Violet||Left rear speaker (positive)||Brown Connector B: Pin 7|
|Violet/Black||Left rear speaker (negative)||Brown Connector B: Pin 8|
|Yellow/Red||Left rear line output (positive)||Yellow Connector C: Pin 1|
|Red/Blue||Right rear line output (positive)||Yellow Connector C: Pin 2|
|Brown/Blue||Common audio ground||Yellow Connector C: Pin 3|
|Green/Red||Left front line output (positive)||Yellow Connector C: Pin 4|
|Violet/Red||Right front line output (positive||Yellow Connector C: Pin 5|
|Black/Red||12 volt switched power||Yellow Connector C: Pin 6|
|Blue||CD changer - Bus On||Green Connector C: Pin 7|
|Red||CD changer - Battery||Green Connector C: Pin 8|
|Black||CD changer - Ground||Green Connector C: Pin 9|
|Green||CD changer - Data||Green Connector C: Pin 10|
|Yellow||CD changer - Clock||Green Connector C: Pin 11|
|Violet||CD changer- Reset||Green Connector C: Pin 12|
|Blue/Green||Telephone audio||Blue Connector C: Pin 13|
|Blue/Yellow||Telephone audio common||Blue Connector C: Pin 14|
|Unused||Blue Connector C: Pin 15|
|Unused||Blue Connector C: Pin 16|
|Unused||Blue Connector C: Pin 17|
|Brown||CD changer - Common audio ground||Blue Connector C: Pin 18|
|Yellow||CD changer - Left||Blue Connector C: Pin 19|
|Red||CD changer - Right||Blue Connector C: Pin 20|
If your car does not have an external amplifier, then the speakers for the Carrera will plug directly into the brown connector B on the back of the radio. If your Carrera has an external amplifier, then there will be a smaller yellow connector that outputs the signals from the head unit to the amplifier. If you have a factory amplifier installed, then you can simply adapt the signal from your new stereo into the leads on the yellow plug, as I have done with this stereo installation. If not, then you simply hook up the speaker leads from the new stereo to the adapter that plugs into the brown connector.
Wire your harness adapter together according to the wiring chart and the instructions included with your new radio. Plug the harness adapter into the factory connector, and then plug the harness into the back of the head unit and connect all of the spade connectors. On this particular head unit, I found that the antenna jack on the back of the unit was not compatible with the one in the factory harness, so I needed the antenna adapter mentioned previously. Plug the adapter into the back of the unit, and then you should be able to plug the antenna cable into the unit. With the new head unit wired up, reconnect the battery, and turn it on to test it. If all of the speakers, radio, and lights work, then install the radio bracket into the center dashboard. This is the bracket that comes with your new unit and typically has tabs that you bend into place once you position the bracket. When the bracket is secure, simply slide the radio into its spot on the center dashboard. Be careful though--most of these units are designed to be easy to install, but very difficult to remove, so make sure that everything works before inserting it into the dashboard.
The radio I chose to use for this project was a Pioneer head unit with a built-in CD player and iPod support. These types of head units allow you to plug your iPod into the stereo and then choose and select songs to play from the stereo itself. In addition, the stereo charges the iPod while it's playing. This arrangement is very cool, but I don't recommend it if you happen to have an iPhone. One of the coolest features of the iPhone is its ability to stream music from alternative sources like Pandora or SimplifyMedia. For iPhone users, I recommend the installation of an FM modulator interface that allows you to play music from the iPhone onto the stereo by emulating a radio station. Using this setup, you can listen to any music on the iPhone and/or any music that may be provided by a music service that streams music over the cell phone network. For example, using the DICE Electronics FM adapter installation detailed in Figure 3, I am able to listen to music streamed off of my home computer, through the cell phone network, and to the car, as I am driving. I'm sure the technology will change and get better as time passes, but this is the best that's available as of 2011.
Another way of playing through the stock radio with virtually no cost at all is by using the AUX input. The factory radio CDR-220 has the ability to take input from an external source. You can purchase a blue connector plug from Becker (PN: 1319.116-276) that will fit into the back of the radio and interface with your external source, or you can tap into the blue plug that is provided as part of the CD changer interface. Tap into and wire up your input source (iPod, etc.) using the three wires that exit out of the blue connector (pins 18, 19, 20). Then turn the radio on, and then hold down the TP button until the message BECKER 1 is displayed. Then turn the tuning knob until the message AUX OFF is displayed. Press the down arrow and change the message to AUX ON. Turn the radio off, and now you have auxiliary input enabled.
The little radio knobs on the stock radios are pretty terrible and often deteriorate with age. You can purchase new ones from Porsche (PN: 996-645-901-00) or check the 101Projects.com for a tip about how to refurbish your old ones.
The Carrera alarm system has a small contact switch located to the left side of the radio compartment that detects removal of the radio. In order to prevent the alarm from repeatedly going off, you need to connect this wire (brown/blue) to ground.
Shown here are the adapter harnesses I used for this installation. A: This harness emulates plug C on the radio and breaks the signal up into RCA jacks that you can plug into the back of your new head unit. Be sure to properly connect up the blue wire as well, which sends the signal to power up the amplifier. B: This plug is the main plug that supplies power to the radio. C: This is the antenna adapter for the back of the new radio. It converts the long tube-style plug into the smaller, European-style connector. D: This reverse antenna adapter is required along with the other one if you are using the iPod FM modulator interface. When connecting the harness adapters, I recommend using simple spade connectors to link the two together. In general, I do not recommend cutting wires in your car--it becomes very difficult to fix and/or restore the electrical system back to stock if anything goes wrong.
Use the radio removal keys (available direct from Becker and also supplied with the factory kit, green arrow) to pull out the radio by inserting them into the head unit and pulling on the two keys using two screwdrivers. The unit should slide right out. The keys release the spring-loaded locking mechanism on the side of the radio (yellow arrow).
Shown here is the new radio ready for installation into the car. The yellow arrow shows the antenna adapter installed. The bracket is installed into the center dashboard (blue arrow), ready for the radio. The factory harness is connected to the adapter, and the connector for the radio is plugged into the back of the new head unit. It's normal to have one or two wires that are not used. In this photo, I plugged in all of the connections and then turned on the ignition to test the proper operation of the radio. I recommend testing prior to the final installation, as these radios are designed to be difficult to remove. New buttons for your stock radio are easy to install--simply pull them off and push on the new ones (inset, lower right). The green arrow shows the alarm radio detection switch, which must be grounded when installing a new unit.
This photo array shows the installation of the DICE universal iPod adapter. A: Here is the FM modulator kit as it comes out of the box. You also need the Scosche VWAKB antenna adapter set (shown in the upper right) to work with the factory radio and its European connectors. B: Mount the DICE unit with double-sided sticky tape. C: Mount it on the underside of the center console and give yourself enough room to access the connectors (yellow arrow). D: Use three tap-in connectors to connect the unit to the 12V supply, the ignition 12V switched supply, and the ground. Plug in the antenna adapters and the inline antenna cable. E: Drill a hole in the back of the storage compartment and route the cable through. F: Test the system and then reinstall the stereo. Although there are many different iPod adapter units available on the market, this particular one has the ability to display the iPod song and artist on the radio through the FM-RDS protocol. I tested the unit and compared the sound quality to the CD inputÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ¢ÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂ"it was indistinguishable. The only small drawback appears to be that the volume level of the iPod interface is a bit lower than simply playing CDs.