wannawagon

I have a 2006 ML320 CDI with Command,

The Head unit will occasionally freeze up - no controls on the head unit work but the volume and change buttons on the steering wheel work - this happens about every month - normally I disconnect the battery for 5 minutes then reconnect it and it works as normal.

Also
The Bluetooth will constantly take a call if you open the door, even if the car has been unused for a day or so, also the Bluetooth will not release the call for ages (maybe 5-10 minutes) after the Key has been removed (or door closed)

Also I notice that if the key is out the stereo can still be turned on (it turns off when key removed but will turn on again if the ON button is pushed on the head unit - and key out) - is this normal.

I also noticed that the unit was quite HOT to touch (like the DVD was spinning etc) even though the car had not been used for an hour. I think it could be draining the battery at times as although the battery is fresh it sometimes it turns over slowly

While I was playing with it today I thought I would see what pins are alive and I noticed the pin 16 (wakeup) seems to be +12.3 to +12.7 for ages (when unplugged from head unit)

I was wondering if the pin16 should only be + 12.x etc for a SHORT while and not the extended time it is on (I kept the voltmeter on for at least 10 minutes), and that possibly the fault is not in the head unit but actually in the message the car is sending

Unfortunately I do not have access to a STAR and the closest dealer is 2 hours travel. I have tried a snapon in the past but could get no codes from the stereo=left

I was considering running the battery + wire through a relay that was activated by the key being in position 2 or above (maybe use the cigarette lighter socket below it to provide the signal to the relay) as the radio keeps memory etc when I disconnect it from the battery=left

Any thoughts would be appreciated

Sorry about the long post