Problem solved thanks for your help everyone, I'm not what I did but the fans working great. I took the fan out to inspect the leads and the connector on the motherboard for damages when I couldn't find anything I put it back together and now the fans work. What did I do?
Before replacing the dock did you try connecting to a different PC I have had that error with a number of devices but it was caused by a faulty USB port.
I haven't had to work on an iPhone yet but it sounds like the battery is faulty which would explain why it overheats when charging and wont hold charge.
I have already had the fan out to clean it which was unsuccessful. I started to think the fan might need replaced but I was talking to a worker at the computer shop that I'm doing work experience at, he said there is a possibility that it could be a problem with the motherboard.
I tired cleaning the fan thoroughly but it still only spins for a few seconds on start up is there any thing else I can try before looking for a replacement fan?