my sat nav says i am somewhere else?

[uS4f]

i have an audi s4 cab 04 model with rnse, no problems with this until recently it says i am elsewhere on the map usually miles away. i took the disk out yesterday for a bit and it worked fine until the same problems occured again today. do i need a new antenna? any help would be appreciated.

 

[uS4f]

i have purchased a new gps antenna i think its the lead that goes through the hinge in the boot which is faulty, this seems to be a common fault on audi cabs, once i get the new lead i will install it in the instrument cluster and will post on here just so someone gets an answer if they have a similar problem. i cant be bothered trying to repair the wire in the hinge.