I have an imported Nissan Elgrand [2003 Rider E51 model]. I have a problem with the tailgate not unlocking, I can open it from inside the vehicle but it will not work on the smart/central locking or the switch on the driver's door. I have had the relay changed but no joy. Any ideas? There is no key hole on the tailgate it is operated by the smart key which works with all the other doors etc and I have replaced the battery in the smart key in case low battery was contributing to the fault.