OK, I had to replace the headphone ribbon cable and associated on/off, volume, etc parts. The phone now thinks the headphone is plugged in when it is not and when i plug in a jack it thinks it is on speaker. When jack not in, volume adjustment brings up the 'headphone' mode on the screen. It is simply all back to front.
Any suggestions (not the plug it in and pull it out 50 times that I found on searching) I am thinking this is an OS problem or of course a faulty replacement part!
Anyone had this problem with a new replacement ribbon cable and control parts? this new one came from Hong Kong and was supposed to be 'OEM' Apple.
thanks in advance...
PS I have tried all the theories in this post and nothing worked.

http://www.hackint0sh.org/forum/showthread.php?t=24896&highlight=headphone+jack[/URL]

OK, just had another replacement cable from hong kong and this one made the iphone go into silly reboot mode... be very carefull who u buy from, obviously these companies are selling duff parts...http://myworld.ebay.co.uk/suntekstore