My dad has a cheap ebay vag com lying around ill give that a go first as it wont cost anything if not then proper one it will have to be lol. I found out today aswell my coolant fan isn't kicking in on hi speed I have twin fans and both run with air con on slow speed. Not sure if it's linked to the boost issue but could be the pre detonation issue I have. I have checked the fuse on the battery and its OK and I have changed the coolant temp swith and the rad fan switch and swaped to another relay or resistor box under the chassis leg on the nearside. Still doesn't kick in. The fans work on high and slow speed if you put power down the connector from the rad fan switch. It has 3 terminals. One is constant live. And other 2 are earthed. If you put power down the either of the 2 earth's then you get high and slow speed depending on which one you put to live. It's sounds like the box under the chassis leg has a relay in it because it clicks when power is put down the wire that controls high speed on the rad fan switch connector. This car loves playing up I tell you. What else could this be. It was a long and quite expensive day again today changing many new parts to
help the old girl. Map? Ecu? Something else? Anyone?, haha thanks for the replies guys.