Possible faulty GPS antenna?

[Iceman2266]

Hello everyone. My GPS stopped working couple of days ago on my 2012 A7, it shows 0 satellites on the MMI.
Audi dealer thinks the shark fin (gps antenna) is faulty, but before I buy a new or used one I want to make sure 100% it's the real issue.
I haven't done a diagnose yet, but will soon.
So my questions are:
1. Underneath the GPS antenna there are 3 inputs, one for gps, one for am/fm radio and last one for GSM/phone (correct me if I'm wrong). The GSM/phone and FM radio still works fine, so how is this possible if the GPS don't receive signal?
2. The aerial amplifier on the left side on the tailgate, does it have something to do with the GPS that can cause no signal?
3. I bought a universal GPS antenna FAKRA RNS-E on eBay, can I disconnect the shark fin gps antenna and swap with this one to check if it's working? If so, where do I plug the new universal antenna? I checked the right side of the boot, but couldn't see any blue FAKRA cable that looks like that one from eBay.

I appreciate all the help I can get :)

[RAF_S7]

The issue is normally caused by water ingress to the antenna module, which causes the GPS issue.

You can plug the FAKRA antenna into the MMI module, which is behind the front dash MMI panel with the CD slot. Very easy to remove, you first remove the AC control panel below the MMI (l think you just pull it out - it's been a while since l did this) then there is one screw holding the MMI in place. The FAKRA connector is on the back of this unit.

The AM/FM antennas are built the rear window, I think the amp module your referring to is for that.

Replacement roof antennas often come up on eBay.

http://etka.cc/audi/part_single/cata.../253429/lang/e

[Iceman2266]

Thanks man, I guess I have to be careful buy second hand antennas on eBay, perhaps they are for sale because they also got water damaged...
But since these antennas are common to fail so often on these cars, it will be better to just use aftermarket FAKRA antenna and place it on the dash right under the windshield. Then the problem will be solved for good?