Need help of installing gps antenna on non-sat nav vf commodore

[mz2017]

Hi everyone, I'm upgrading my non-gps vf2 sv6 with factory gps head unit, thanks to @Tasmaniak for his fantastic post otherwise I have no clue of how to dissemble these things... anyway long story short after the magic moment when I plugged the flash box (sourced from ebay) to obd2 port and the head unit unlocks in literally 3 seconds, here comes the frustrating part, there's no gps signal due to aerial issue...

but I want the factory aerial like this:

now there're couple of questions messing around:
1.
the seller suggests me some aftermarket gps module like this:

but I don't know how to set up... the wire interface of the head unit is exactly the same with my old one and I figured out one of the plugs may be the the one that receives gps signal, but it's currently used for AM/FM, which means if I plug the gps instead, the radio is gone, other than that I doubt the gps signal might be affected as well because the only way I can think of to fit it in is to squeeze everything into the head unit housing under dashboard:

and I'm curious how does the aftermarket integrated gps system works, do they also put gps antenna behind the grey box head unit and push it in?
http://www.naviplus.com.au/holden-mylink-gps-navigation-upgrade

2.
I searched for factory antenna and spot the clear difference:

so the gps antenna has a larger base and two plugs, while non-gps antenna only has one. However I have no idea how to swap it, there're no external screws or whatever, maybe I need to remove the lining from inside first...

 

[mz2017]

for anyone who's interested of head removal and unlock there're some extra pics,

my non-gps unit and gps unit, same look but gps unit has an extra socket

the annoying plug mentioned by @Tasmaniak , need to flip the buckle first and pull out

the screen shows locked after swapping

the flash box, works like magic
I bought it here:
https://www.ebay.com.au/itm/VF-SERI...232713?hash=item466ae6f949:g:JSgAAOSwHhRa4iC8
you need to send it back after use to get back deposit though

system unlocks... unfortunately no gps signal

 

[dgp]

To replace the antenna, you need to remove the headlining.

 

[dgp]

Remaining pics of procedure

 

[mz2017]

Remaining pics of procedure

View attachment 200115 View attachment 200116 View attachment 200117 View attachment 200118 View attachment 200119 View attachment 200120

Thank you very much dgp, unfortunately I have to give up factory whip aerial because I only found today that the sockets of head units are actually different... big mistake! There's a dedicated port for gps signal which I didn't notice, so an extra cable needs to be added to the cable bus to suit factory aerial.

I'm searching youtube for aftermarket antenna installing and there're plenty of them, usually glued under dash board. Of course the signal will not be as good as putting on the car roof but I'll see.

non-sat nav head unit

sat nav head unit, blue port for gps

 

[Mavericks Choice]

Have fitted other A/M GPS units to various cars, you won't lose much signal by fitting the GPS antenna under the dash.

 

[Skylarking]

Thank you very much dgp, unfortunately I have to give up factory whip aerial because I only found today that the sockets of head units are actually different... big mistake! There's a dedicated port for gps signal which I didn't notice, so an extra cable needs to be added to the cable bus to suit factory aerial.

I'm searching youtube for aftermarket antenna installing and there're plenty of them, usually glued under dash board. Of course the signal will not be as good as putting on the car roof but I'll see.

If you did decide to go with the standard GPS antenna and thus remove the headlining, that would be the ideal time to also do the electriochromatic mirror and sunshade lamp upgrade and why not add front and rear chresh cams Go the whole hog, no expense spared

 

[joban]

for anyone who's interested of head removal and unlock there're some extra pics,

my non-gps unit and gps unit, same look but gps unit has an extra socket

the annoying plug mentioned by @Tasmaniak , need to flip the buckle first and pull out

the screen shows locked after swapping

the flash box, works like magic
I bought it here:
https://www.ebay.com.au/itm/VF-SERI...232713?hash=item466ae6f949:g:JSgAAOSwHhRa4iC8
you need to send it back after use to get back deposit though

system unlocks... unfortunately no gps signal