Review on In Car Female 3.5mm AUX Audio Adapter Cable for BMW E39 E53 X5 X5M Z4 E83 E85 E86 X3 Mini Cooper - Enhance your In-Car Audio Experience! by Anthony Payton

Direct plug and fast play product. I have a 2006 z4 3.0si with a business receiver. The plug fitted the back of the radio perfectly, long enough to mount to my liking. I specifically ordered this cable instead of the others because it had a built in plastic sleeve that contained a small circuit with resistors connecting the left and right channels so the radio would see a high resistance. After installation I removed the cable, tested and tested for end-to-end continuity, but there was no resistance between the left and right channels. I opened the keg and checked the components and found no resistance between the channels. I know the radio is supposed to be high impedance and the DIY community has settled on 300k ohms. To test the theory I soldered 3 100kΩ resistors in series between the left and right channel wires and was able to instantly switch to the AUX option on my radio. I can only assume it had a faulty resistor circuit out of the box. I do not blame the seller and I have never written any problems with my order. I just jumped into the install and was able to change it to work without waiting for the refund/replacement process.