need help... one time i went to san francisco.. i was at bay bridge and suddenly my arrow position went out of track and went to the pacific ocean... and most of the time on close curves especially those Y road... my arrow get lost always.. what are the things i need to do??? did the installer forgot to calibrate my position? how do i do that because i can see my gos antenna has a good position it is located on my top left corner windshield, it was positioned on top of a my glass windshield and is not touching any metal...

You may need to put the antenna on the dash with the plate under it and make sure they connected your VSS wire.

the thing is i didn't install the unit and i'm not good at this one.. i dunno what a vss is.. and the antenna's wire run underneath the side panels... so i dunno how to transfer it... thanksss

Ok,since you paid to have it installed then you should have a warranty.Take it back to them,and tell them what your problem is and they should correct it.They should know since they're professionals.