Volume Control

Ever get tired of having to turn the radio volume up and down when changing speeds? One of the first "problems" I ran into with my car was the apparent lack of Speed Dependent Volume (SDV) control. The user manual said the radio supported this feature yet it didn't seem to work. The dealer even reprogrammed the radio in order to get it to work - all to no avail. After a bit more research it was discovered that when the audio system also has a DSP unit then the DSP provides the SDV capability. The problem is that the amount of additional volume provided is nearly non-existent. It turns out that the radio still has the capability but the required signal is not provided. This hack solves that oversight. The credit for this hack goes to Mark (DFW, TX) Gluck. I simply followed his directions (with some minor modifications) and documented the steps I took. I have a few of the pins available for those that would like one. Just drop me an e-mail along with your snail mail address. Once I run out of the pins that I have it will be necessary to order a replacement harness from Becker (p/n 1163.736.276).
	The first thing to do is obtain the radio removal keys if you don't already have a set. I got mine for no charge from Becker by calling the parts department (888) 423-3537 x209. NOTE: You will need to enter your radio code when done.
	Use the keys to extract the head unit from the enclosure. Pull firmly to remove the radio. Be sure you have your radio code handy as it is necessary to remove power from the radio. Once power is reapplied it will be necessary to re-enter your code.
	It is also necessary to remove the carpeted side panels. Just grab them at the back edge and give a sharp tug. Do this to at least the drivers side. I removed both panels in order to make routing the new wire a little easier.
	Removal of the panel shows the snap-in retaining clips that hold the panel in place. The panel side of the retainer is plastic. Be sure things are lined up prior to trying to reinstall the panel or you risk breaking the carpet side of the clip.
	Collect all of the other parts needed to do the upgrade. This includes the Becker wire and pin as well as some #18 stranded wire (Radio Shack p/n 278-1226). The wires may be joined several ways. I chose to solder mine and use heat-shrink tubing. The original instructions used quick disconnects (Radio Shack p/n 64-3049A).
	Here are the wires soldered and ready for the heat-shrink tubing to be put into place. The tubing may also be shrunk by using a match or lighter - although care must be taken not to apply too much heat!
	After removing the radio unplug the 3 connectors. Your situation may have more connectors if you also have the CD changer. The connector we're interested in is the lower black one - labeled 'A' in the manual. Of note is the small yellow square at one end. This must be pulled at least part way out in order to insert the newly made wire.
	Here is a view after extracting the retainer by using a small screwdriver. A paper clip or any other small tool should be able to get under one edge in order to lift the locking bar.
	Insert the newly made wire into the number 1 pin position. The connector is clearly labeled, depending on one's eyesight. The position may be double checked by referring to the owners manual if needed.
	Route the free end of the wire through the first few inches of the cable wrap. This will serve to dress up the installation and also make the hack less visible if the radio is removed in the future. Next, route the free end out the back of the opening and down to the console area that was exposed by the carpeted panel removal.
	Route the wire under the velcro straps that hold the carpet together and in the carpet seam to the front of the driver's side footwell. Finally, tuck the wire under the top edge of the carpeting. Now run the remaining wire around to the relay panel and remove the cabrio relay. It's tough to miss as it's the only double size relay.
	The last step is to connect the wire to the speedometer signal. This is accomplished by sharing the connection used by pin 18 on the cabrio relay. I simply plugged the free end of the wire into where pin 18 normally resides. I also bent over pin 18 which also performs the cabrio relay hack. This step is optional but makes it easier to plug the wire in.
OK, so now what? In order to make use of this hack the radio "GAL" setting must be enabled. I use a value of 7 which seems good to me. If you always drive with the top up then a lesser value may be adequate. To set the GAL setting simply refer to the instructions in your radio manual. By the way, this hack does not defeat the SDV capability of the DSP unit - it simply adds to it. To verify the operation of the SDV just go for a drive. It is most evident at speeds over 40 MPH. It can also be verified by turning the radio off then back on when at speed. The radio starts out at a normal level and then the volume adjustment is made based on the current speed of the vehicle. Happy listening!