Situation

When the above vehicles are equipped with hardtops, the relay which is responsible for adjusting the sound volume of the Harman-Kardon audio system operates incorrectly.

There are two paths for volume adjustment: "top closed" and "top open". This differentiation is realized by a relay.

Due to a fault in the relay control, the sound volume adjustment on cars with hardtops is influenced by the heated rear window (audio volume "jumps" higher when rear defogger is turned on).