L322 audio volume faint with iPhone

G’ day!
Last autumn I bought a 2005 (June) L322 Autobiography to replace a cherished ’92 Classic LSE.
Given its complex systems and the limited time I have, it has taken me a while to find my way around the complexity of the L322.
The car is equipped with a lead for iPod/iPhone connection (presumably fitted by a dealer) which is connected to the “Aux In” on the Harmon Kardon Logic7 audio unit. Connecting an iPhone to this lead allows it to play music through the Aux In on the HK system (but not charge the phone). However the volume is faint when compared with the HK in radio mode. Pressing the Logic7 button somewhat improves matters but not enough to be satisfactory when driving.
If anyone has experienced anything similar I really would appreciate knowing how to sort this.
(The really annoying thing is that the Bluetooth connection to the phone hands-free unit works well so it would be overkill to fit something like a Parrot Mki 9200 merely for the music.)

have you turned the volume up on the iphone first?

Yes, it's on full!

Another detail I forgot to mention - I am using an iPhone 3GS

3.5mm jack connection or
dock connector?

Try cycling through the head unit settings, not sure on the L322 but most head units have an aux boost level.

The lead is fitted with an Apple compatible dock connector.

if connected properly when connected you shouldnt be able to adjust the volume on the ipod/iphone
if its letting you select volume on the iphone then somethings up.

Thanks for these helpful ideas guys.

I have just checked - there is no control over volume on the iPhone when it is connected via the docking port using the Apple compatible plug on the Aux In lead. [When I said I had volume up high I was referring to the state before connection.]

As to cycling through the audio controls, I have been trying that without making any difference to iPhone audio volume. I have reset all the various reset buttons within audio and no joy. In fact I worry whether pushing to many buttons may not cause the system to (partially) lock up and I am wondering whether there is any way of re-booting the head unit without going to a dealer for a software re-install?

It's the same on our disco 3. I have the radio on abut 12 and my iphone on about 20. Is that what you mean?

I think it's a common situation and not necessarily a broken problem. I have the same on my disco3 although that is using a 3.5mm jack plug.