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Recommended Posts

Posted

As many of you have no doubt been frustrated with the lack of a decent solution for using your iPod with your CDR23 equipped Porsche, you may be interested in this approach. I'm doing this in my '04 GT3, where ultimate audio quality is not necessary or usable (it already makes great music) but I do want better than the wireless FM modulator provides (very poor in FM Station rich Bay Area). I purchased a "wired FM Modulator" (mine is Clarion, $19.95 from the local after market installer). I've mounted it in front of the radio (on the firewall, accessible when you remove the radio and the climate control module. Power and ground currently come from the Becker A connector pins A4 and A8, which thus require an external power switch (a PITA I intend to fix). When you turn off the power to the FM modulator an internal relay connects the regular antenna and the radio works about as before. When the FM modulator is on and the radio is tuned to its output, you get (nearly) interference free FM quality on that channel.

The challenge is eliminating the external power switch for the Modulator. I tried the "switched battery" connection (terminal D9 on the climate control module, blue-black wire); this, unfortunately only has power while the ignition switch is on. I want the modulator to work exactly like the radio (ie remain on when the ignition is turned off but key is in ignition sw). Thus I turned to the "antenna power" connection on the Becker.

As best I could guess, this provides power to the antenna preamp (duh-"antenna power"!). BUT, that doesn't seem to be true. I cut this wire, and the radio continues fine (could be due to strong FM station bypassing preamp) but, and this is the killer: this lead has power on it after the radio shuts off and the key is out of the ignition. Doesn't make sense.

Any ideas? Btw, the Becker plug wiring is attached.

post-2529-1146530703_thumb.jpg

Posted
.... but, and this is the killer: this lead has power on it after the radio shuts off and the key is out of the ignition. Doesn't make sense. Any ideas? Btw, the Becker plug wiring is attached.

What you are describing sounds like the lead for a power antenna (which we don't have, of course). In a car with a power antenna, the antenna lead stays hot (even after key is removed) so that the antenna can retract. Antenna motor then shuts itself off via internal contacts. Could it be that Becker includes this as part of a universal wiring set up ... in case the radio is used in something other than a 996?

  • Moderators
Posted

Most in-line FM modulators turn themselves on and off automatically when they sense a line-in signal from the audio source that you are adding to your radio (the iPod). I would suggest that you simply use either the switched or unswitched 12v+ that is available at the pre-wired telephone cable that is in the center console under behind the "batwings".

mysterycable.jpg

Does your in-line modulator have to be manually switched on and off? If so you should consider taking it back for one that turns itself on and off.

Posted

I believe that in an '04 996 that the white wire in question powers either (1) the diversity amplifier as Loren points out, or (2) a single antenna amplifier in cars without the upgraded audio system (such as my GT3). The factory wiring diagram shows both options. It may be possible that the CDR23 antenna power is on for a "long time" after key removal to support power antennae; I'll look at that option. I did measure the load current drawn in this wire (it is about 50 mA continuous) which syncs with an antenna LNA, and it could be on all the time at this low draw (but I doubt it).

Posted

I was dealing with the same issue along with installing a V1, a power adapter for my MP3, and a laser jammer. I ended up buying a blade fuse subpanel from Autozone, split the terminal (cut the brass insert- 3 switched, one unswitched) then wired the switched and non-switched wires from the phone plug to the new panel. I closed the connection to the fm modulator, cut off the fuse holder and wired it to the unswitched fuse. I removed the fuse holders for the V1 and laser system and wired those to the switched side of the subpanel. I then took the power adapter (cigarette lighter insert) removed the stepdown voltage converter and wired that into the switched side of the fuse block.

The panel can be attached in the foot well next to the fuse box. The wiring harness can be made with heat shrink tubing. Basically, all the above is just a variation on the theme of using the telephone plug.

  • 1 year later...
Posted
The +12 volts on A5 goes to the Diversity Antenna (amplifier).

As in, I need to supply 12volts for the antenna amplifier <or> this lead\wire supplies 12v?

I think this might be why my radio reception is so poor. I don't have anything connected to A5 (white).

  • Admin
Posted
The +12 volts on A5 goes to the Diversity Antenna (amplifier).

As in, I need to supply 12volts for the antenna amplifier <or> this lead\wire supplies 12v?

I think this might be why my radio reception is so poor. I don't have anything connected to A5 (white).

Your car is a MY99 - different radio.

Here is your schematic for the antenna.

post-1-1199491068_thumb.png

Posted

Your car is a MY99 - different radio.

Here is your schematic for the antenna.

post-1-1199491068_thumb.png

Actualy I have the "enhanced audio m490 package" so the schematic looks more like the attached - my earlier post was actually referencing the schematic - let me know how you read it. To me it looks like position 5, white wire (which I did not have connected previously). It's in the same harness\connector with the speed wire, ACC, BAT, etc.

Regardless I've completely gutted the entire terrible stock "enhanced" system with a Pioneer AVIC-Z2. The only thing I've kept are the stock speaker wires, which were sufficient guage for the cockpit volume\speaker size selection.

I've connected the white white - position 5 to my stereos blue\white "power antenna" lead, which is used to either power an antenna retraction motor or diversified "windshield" antenna.

Reception has improved dramatically, and this might have solved a ground loop problem I was having.

Thanks for the reply.

post-25029-1199497962_thumb.jpg

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