Converting symphony II antenna system use with RNSe
This should be of interest to those of you with 07 and later cars with the newer style headunits, especially if you have since fitted an RNSe and got the "ZF short to Earth" issue in VCDS not to mention degraded radio reception.
If you've been following my threads on Navplus (Audiforums.us) you'll know I've been using a Golf module to restore "diversity" in the antenna system. This works great, improved reception, but still the ZF short to earth issue, not a huge problem, but it has bugged me since fitting the RNSe.
On 07 and newer cars Audi changed the way the antenna system works. This diagram gives you an idea. The top part is the Phase Diversity system used on newer cars, the lower part shows the Switched Diversity system required for the RNSe.
So this weekend I managed to get around to installing the required parts to convert my existing antenna system back to the old system.
First I removed my existing golf module which was mounted behind the RNSe. I have to say that the Golf module has served me well and certainly improved my reception. However it doesn't cure the ZF short to earth issue.
Fitting the new bits was quite straightforward. The tricky bit was taking the trim off the boot lid. There are two torx screws to remove, then you have to lever from the bottom corner of the trim making sure you don't scratch the paint or bend anything. I used a long screwdriver wrapped in a cloth. It's held on by several spring clips, you can see where these are once you manage to pop the corner clips and can see behind the trim. You'll need a long lever to reach in and pop the remaining clips off. Once off you can see the lower antenna amp. You'll also have to remove the trim around the top of the window, again two torx screws and several more spring clips hold this on. Once you've removed this you'll see the upper antenna amp.
Here's a pic of the bits, you can buy them all from you local dealer, including the Fakra cables.
and a parts list..
000 098 652A 1.5m female to female Fakra cable (you can get away with a 1m cable, 000 098 652) (£12)
000 098 692 30 cm male to male Fakra adaptor (£12)
8P4 035 225B Upper antenna amp (£14)
8P4 035 225 Lower antenna amp (£150)
1C0 973 119B Three pin connector housing x2 (£1.50 each)
000 979 009 Repair wires x3 (£1.20 each, cut them in half to give 6 wires)
As you can see from the picture above the new lower antenna amp has two extra connectors, 1 Fakra and 1 three pin plug, both circled. The extra Fakra connector is the ZF feed from the RNSe. This will be connected to the Fakra cable which is currently connected to the upper amp. The new upper amp will be connected back to the new lower amp via the two three pin connectors and repair wires. You'll have to make a small loom (I made mine 86 cm long) and wire pin 1 to pin 1, pin 2 to pin 2 & pin 3 to pin 3. This pic should help.
The old lower amp is help in by 3 x 10mm bolts. Unplug the cables first, the three large plugs on the back of the unit (see pic below) have a small red tab which needs to be pulled out before they can be unplugged.
The new amp is a direct replacement. Here you can see the extra Fakra (green plug) for the ZF connector and the 3 wire loom (yellow wires) going to the new upper amp.
and the new upper amp.
Run all the new cables at the side of the existing Audi cables, use cable ties or loom tape if required. When I first switched on there was a short delay then all the FM stations popped up as normal. A quick VCDS scan revealed a few faults relating to unplugged antenna amps. I cleared these out and after a few engine starts can confirm that they didn't come back. So it looks like we have a working fix. I'll keep an ear on FM reception this week and post back if there are any issues.
I'll hang on to my old bits for a short while, but if anyone would like to make use of my old Golf module and cables or would like to use my old amps (8P4 035 225D and 8P4 035 225C) in a symphony II to symphony II+ "reverse fit" situation drop me a PM.
EDIT: 8P4 035 225D and 8P4 035 225C now sold
EDIT: Diversity module now sold