Porsche Wiring does NOT follow a logical pattern - Surprised?!
Posted: Thu Jun 14, 2018 9:00 am
As you all know, I've been working on getting my CDR-220/Harman stereo system in my 996 back to factory setup since the "glue people" made such a royal mess of things. For those that don't know to whom I'm referring to - the "glue people" are one of the previous owners that installed or hired installers for the last stereo/K40 radar detection system. Their work is some of the sloppiest I've ever seen in my lifetime. Instead of using proper mounting hardware, they sprayed glued everything. Fortunately, they didn't cut out all the factory OEM wiring and I think there just might be light at the end of this wiring repair tunnel. However, when I was replacing the speakers because the OEM HAES speakers were dry rotted, I noticed the polarity didn't line up with the DIY diagrams people put online.
Based on everything I've seen posted on the forums, solids are positive and stripes are negative, right? Wrong! Let me tell you why. Please ref to the attached image.
This doesn't surprise me at all. Porsche is very clever to maximize profitability by forcing you to upgrade, cross grade, or replace when it's not necessary. For example, Porsche makes two almost identical M490 6x40W amps for the 996 - one is labeled "coupe" and the other "cabrio". Basically, the only difference is the 12V/Ground are wired slightly different on the connector. The 20 pin connectors have prevention tabs to avoid crossover. Notice the cabrio is blue and the coupe is natural color. The DSP version is brown. The smaller input multipin connector is the same on both models.
But that's not where things get a hairy. Here it goes... As I was removing the door panels to replace the 5.25 speakers, I noticed the factory lines were BOTH green and green/brown on BOTH doors. Huh? The RIGHT Front side is supposed to be Violet and the LEFT front side green. Both cables in the doors were untampered with and still had the factory connections. But then I noticed the solid green lines were feeding the negative terminals on the speakers! double what!????? I thought... Aren't the solid speaker lines supposed to be POSITIVE!? I went and got my multimeter and sure nuff, the green was negative and the green/brown line was positive. I then checked the output from the amp and same thing... it was reversed. Why? Could it be a bad amp? Could the glue people have cut and reversed the lines? I scratched my head and then pulled up the schematic in the shop manual and found the proof in the pudding .... I couldn't believe it. Here's an attached example of what I found...
Notice inside the red circle. It notes the right door line is Violet and then changes over to Green. (see the break in the line?)
Trace the solid green and violet line back to the amp - notice the amp says the solid line to the speaker is NEGATIVE.
And, the GRN/BRN and VIO/BRN are both positive lines!
UGh!!!! So much for trusting the info on the forums I've read in the past. The best advice I could give someone repairing or upgrading their sound systems is... check all line continuity with a multimeter and if you're troubleshooting cabling to a factory setup, make sure you have the schematic from the shop manual.
Cheers my 996 brothas!
Based on everything I've seen posted on the forums, solids are positive and stripes are negative, right? Wrong! Let me tell you why. Please ref to the attached image.
This doesn't surprise me at all. Porsche is very clever to maximize profitability by forcing you to upgrade, cross grade, or replace when it's not necessary. For example, Porsche makes two almost identical M490 6x40W amps for the 996 - one is labeled "coupe" and the other "cabrio". Basically, the only difference is the 12V/Ground are wired slightly different on the connector. The 20 pin connectors have prevention tabs to avoid crossover. Notice the cabrio is blue and the coupe is natural color. The DSP version is brown. The smaller input multipin connector is the same on both models.
But that's not where things get a hairy. Here it goes... As I was removing the door panels to replace the 5.25 speakers, I noticed the factory lines were BOTH green and green/brown on BOTH doors. Huh? The RIGHT Front side is supposed to be Violet and the LEFT front side green. Both cables in the doors were untampered with and still had the factory connections. But then I noticed the solid green lines were feeding the negative terminals on the speakers! double what!????? I thought... Aren't the solid speaker lines supposed to be POSITIVE!? I went and got my multimeter and sure nuff, the green was negative and the green/brown line was positive. I then checked the output from the amp and same thing... it was reversed. Why? Could it be a bad amp? Could the glue people have cut and reversed the lines? I scratched my head and then pulled up the schematic in the shop manual and found the proof in the pudding .... I couldn't believe it. Here's an attached example of what I found...
Notice inside the red circle. It notes the right door line is Violet and then changes over to Green. (see the break in the line?)
Trace the solid green and violet line back to the amp - notice the amp says the solid line to the speaker is NEGATIVE.
And, the GRN/BRN and VIO/BRN are both positive lines!
UGh!!!! So much for trusting the info on the forums I've read in the past. The best advice I could give someone repairing or upgrading their sound systems is... check all line continuity with a multimeter and if you're troubleshooting cabling to a factory setup, make sure you have the schematic from the shop manual.
Cheers my 996 brothas!