Quote Originally Posted by AuldBM View Post

I have this exact problem on a 318i ES (2003). IPNA threw up the error and I can clear it for a second. I'd hoped the yellow switch mentioned above would be the root cause. I've had a look and all seems well.

Attachment 44641Attachment 44642Attachment 44643

Can anybody give me an idea where to look now?

I also have another couple problems that may be related.

Keyfobs not working or programing (FZV wiring?) & a terrible AM radio reception.

key and reception issue will be your aerial amplifier.
is in rear of car pillar. clean rear window heater lines and connections with electrical contact cleaner
discconect amplifier and clean that up and try again.
if it doesnt work you may need a new one, or a repair to the contacts of your rear window if there is any damage to the connections