Audio Systems: 2010 vw harmon kardon hd radio, vw jetta tdi, vw jetta

Question
i sold a gentleman a 2010 vw jetta tdi with the harmon kardon navi and stereo system.  he has been in several times to troubleshoot a few problems with it.  the current problem is that his HD radio is on but it does not work.  this is the same thing that is happening in the other 2010 models that are not yet sold.  our vw technicians cannot identify the problem, would you have any insight on how to get the HD radio to work.  something else maybe you might need to know, we are in new mexico so there is only 1 HD station offered in our area.  would this have anything to do with it?

Answer
how close are you to the US ? maybe that is the problem

All Mexican radio stations within 320 km of the U.S. border are allowed to transmit their programs on the AM and FM bands utilizing HD Radio technology. Approximately nine Mexican AM and FM stations are already operating with HD Radio technology along Mexico’s border area with the US. Groupo Imagen has commenced HD Radio transmissions on XHDL and XEDA in Mexico City during June, 2008.