Hi all and thanks for taking the time to read this.

I have an 08 plate vectra C with the CD70 Navi(with Aux-in as standard) HeadUnit.

I have a weird problem which I can't quite workout whether it's the phone or the HeadUnit.

When I attach my HTC desire to the Aux-In, it's very quiet.

I proceed to the volume selection screen on the CD70 and when I select the Aux-In volume control only, the volume of the Aux-In increases immediately to a normal level. This is without moving the slider bar of the Aux-In volume. If I move the slider, the volume increases or decreases depending on direction, but when I exist the volume selection screen, it reverts to quiet. If I enter the screen again, the volume increases without changing the slider bar. Exit again and it reverts to quiet.
This happens all the time.

The HTC phone is in an HTC car kit and is in Car Mode when in operation.

When I tried this with an iPhone and iPhone car kit, this all worked out of the box and Aux-In volume was fine.

I'm starting to think that the HTC Phone + car kit doesn't give the correct line out volume to be used on the Aux-In on a CD70.

Anyone else has an HTC desire connected to a CD70 Navi Aux-In or has experienced the weird problem with the Aux-In volume controls?