Rear Hatch Trim Re-Fitting, How To.

[PlasticMac]

I think, () I've fixed the poor FM reception issue which has frustrated me for months. It seems to have been a poor power connection at the Diversity controller.
I'm struggling to get the large, lower trim back on, having already refitted the upper side trims, (removed to check out the antenna amps).
So, wondering if it best to fit the two upper side trims first, or the large lower trim first, then the side trims. Any advice from someone who has to experience please?
Mac.

 

[Deleted member 20348]

You are correct in what you described.
All the window trim first followed by large lower trim.
The large trim slots either side of the boot latch.
Line up the trim clips and do some firm thumps with the bottom of a clenched fist all around the edges

 

[PlasticMac]

You are correct in what you described.
All the window trim first followed by large lower trim.
The large trim slots either side of the boot latch.
Line up the trim clips and do some firm thumps with the bottom of a clenched fist all around the edges

Thanks, I thought so, but confirmation is, (nearly), always reassuring.
I'll inlist an assistant, and try again. Probably best to leave it a few days, to make sure the FM is really OK.
Mac.

 

[Proghound]

If you're flexible enough, with the rear seats out I understand you can fit the lower trim back from inside the car with the boot shut, so you don't have to both hold the boot down and thump the trim clips home from underneath.

 

[PlasticMac]

If you're flexible enough, with the rear seats out I understand you can fit the lower trim back from inside the car with the boot shut, so you don't have to both hold the boot down and thump the trim clips home from underneath.

I'll get my tube of Volterol ready for a preparitry rub down. Makes sense though, since the trim fits inside the car when closed. Will report back.
Mac.

 

[Howey]

I think, () I've fixed the poor FM reception issue which has frustrated me for months. It seems to have been a poor power connection at the Diversity controller.
I'm struggling to get the large, lower trim back on, having already refitted the upper side trims, (removed to check out the antenna amps).
So, wondering if it best to fit the two upper side trims first, or the large lower trim first, then the side trims. Any advice from someone who has to experience please?
Mac.

How did you rectify the poor power connection please?

 

[PlasticMac]

How did you rectify the poor power connection please?

The failed connector was the small, flat connector, (pictured below). It is a 3 pin connector, with only two pins used, ground and unswitched 12 volts.
The ground was high resistance, only traced when I found the antenna cable to the radio had a high resistance to ground, which took me to the Diversity controller.
I cut the failed connector off, and then soldered a short length of cable, with matching connector, to the cut ends, and insulated with heat shrink.
The failed connector looked OK, but I can only guess that the socket pin had opened up.
From only being able to pick up a poor signal from Radio 2, with intermittent station ID via RDS, I can now pick it up on at least three frequencies, with constant RDS station ID.
I've been trying to find this fault for months, replacing, or checking, all four rear screen antennas, and their amps, the Diversity controller, and associated wiring.
Fingers crossed that is really is the fix.
Mac.

.

 

[Howey]

The failed connector was the small, flat connector, (pictured below). It is a 3 pin connector, with only two pins used, ground and unswitched 12 volts.
The ground was high resistance, only traced when I found the antenna cable to the radio had a high resistance to ground, which took me to the Diversity controller.
I cut the failed connector off, and then soldered a short length of cable, with matching connector, to the cut ends, and insulated with heat shrink.
The failed connector looked OK, but I can only guess that the socket pin had opened up.
From only being able to pick up a poor signal from Radio 2, with intermittent station ID via RDS, I can now pick it up on at least three frequencies, with constant RDS station ID.
I've been trying to find this fault for months, replacing, or checking, all four rear screen antennas, and their amps, the Diversity controller, and associated wiring.
Fingers crossed that is really is the fix.
Mac.

.View attachment 119485

Many thanks for that detailed description and indeed crucial picture, that's certainly an interesting find!!

 

[Robin_Cox]

The ground was high resistance, only traced when I found the antenna cable to the radio had a high resistance to ground, which took me to the Diversity controller.
I cut the failed connector off, and then soldered a short length of cable, with matching connector, to the cut ends, and insulated with heat shrink.
The failed connector looked OK, but I can only guess that the socket pin had opened up.

For someone who is an electical imbecile, when you say "high resistance to ground" - what does this mean in practical terms? I do have a multimeter, although I've never been able to make it detect anything through the attached probes in any setting on the front dial. I take it this is the small unit that is slotted down the back of the battery compartment ? I got a replacement one off here a couple of years back but swapping it over had no effect on the bad reception suggesting it may be the wires rather than the unit that are the issue and it seems likely that a simple single point of failure causing the entire unit to be dead may be the easiest thing to diagnose / fix.

 

[PlasticMac]

For someone who is an electical imbecile, when you say "high resistance to ground" - what does this mean in practical terms? I do have a multimeter, although I've never been able to make it detect anything through the attached probes in any setting on the front dial. I take it this is the small unit that is slotted down the back of the battery compartment ? I got a replacement one off here a couple of years back but swapping it over had no effect on the bad reception suggesting it may be the wires rather than the unit that are the issue and it seems likely that a simple single point of failure causing the entire unit to be dead may be the easiest thing to diagnose / fix.

 

[PlasticMac]

I dissconected the aerial, the ISO connector at the corner of the radio, not the white Fakra connector in the centre.
Set the multimeter to ohms, connecter one lead to the body, (hinge fixing bolt is convenient), and the other to the shell of the aerial connector. It should read zero ohms, maybe 0.1, but no more. Mine read about 3.0 ohms, which in this context is high resistance as it should be a "dead short" a direct connection.
From the circuit diagram, it should be connected to ground/earth via the Diversity controller, to which it's connected. The Diversity is grounded via that power connector.
It could have been the aerial cable, (unlikely but possible), so I unplugged the white Fakra connector, which is the Diversity end of the aerial cable, and still on ohms, measured between the negative battery terminal, and and the outer ring of the Fakra plug, (pic below), on the Diversity controller, and, again saw about 3 ohms.
That clinched it.
I'll give it a fee days, to be sure though.
I have a spare cable end, as both @Ami and @timmus sent me one. Yours if you need it.
Mac.

 

[PlasticMac]

Cars with a Concert will have five separate antenna, (one AM and four FM), in the rear screen. Cars with Chorus have two, (one AM and one FM). There are four antenna amps in the Concert/Diversity setup, (one AM & FM, and three FM. Chorus has one antenna amp, AM & FM).
In the Chorus application. The amps are powered via the coax cable. The single Chorus amp from the head unit, and the four in the Concert version are powered from the Diversity controller.
So a power supply problem to the Diversity affects both the Diversity controller, and the antenna amps, (so little signal from the antenna circuits).
Lastly, the Concert needs to be coded to talk to the Diversity controller. If you have replaced the Concert, check the coding, as the same radio is used in other Audis, (Mk1 TT), which has no Diversity controller, so not coded for an A2.
Hope this helps.
It's an Audi, after all!
Mac

 

[PlasticMac]

If you're flexible enough, with the rear seats out I understand you can fit the lower trim back from inside the car with the boot shut, so you don't have to both hold the boot down and thump the trim clips home from underneath.

The trim doesn't fit, from inside, with the hatch closed. It's too wide at the top.
Wedge the hatch open, to give about 150mm gap at the bottom. Prop something against the outside, so you can push without the hatch moving.
I used a dense foam block to wedge it open, which I positioned above the top of where the lower trim fits so it doesn't get in the way. And a rolled up rug leaning against the outside.
I also removed the pull tab from the manual release cable, and tied a piece of string to it, and out through the tab recess.
I folded the seat backs down, and they then are just right to sit on!
Fit the manual release cable into the release lever.
Guide the trim in place, especially into the hatch catch cover groove, and once it's in position give it a few firm the thumps with a clenched fist, starting at the top.
The fixing clips at the bottom of the trim may need a push upwards to find their slots, this is best done with the top clips fixed, and the hatch open. With a torch, you can see the clips and their slots. Push them up, in line with the slots, starting from the left hand side, working to the right hand grab handle last.
Pull the string, reattach the tab, and you're done.
Mac.

 

[Andrew]

The trim doesn't fit, from inside, with the hatch closed. It's too wide at the top.
Wedge the hatch open, to give about 150mm gap at the bottom. Prop something against the outside, so you can push without the hatch moving.
I used a dense foam block to wedge it open, which I positioned above the top of where the lower trim fits so it doesn't get in the way. And a rolled up rug leaning against the outside.
I also removed the pull tab from the manual release cable, and tied a piece of string to it, and out through the tab recess.
I folded the seat backs down, and they then are just right to sit on!
Fit the manual release cable into the release lever.
Guide the trim in place, especially into the hatch catch cover groove, and once it's in position give it a few firm the thumps with a clenched fist, starting at the top.
The fixing clips at the bottom of the trim may need a push upwards to find their slots, this is best done with the top clips fixed, and the hatch open. With a torch, you can see the clips and their slots. Push them up, in line with the slots, starting from the left hand side, working to the right hand grab handle last.
Pull the string, reattach the tab, and you're done.
Mac.

Good Evening Mac,

Strange, I remember there was no problem with fitting trim with boot closed.

Andy

 

[Robin_Cox]

much appreciated! I will try to find the multimeter and follow your instructions once weather improves enough here to get out on the drive and have a delve in the battery compartment.

 

[CrispyEdd]

I too have had same issues as @Robin_Cox , I followed same logic and had same results as you Robin. Very frustrating as the head unit is the nicest looking and I didn't want to swap it. This is a great find from @PlasticMac and no doubt will benefit a lot of fellow audio bereft drivers!!

Can the plug be replaced with a spade connector and wrapped or does it have to be the plastic plug off a donor car?

 

[PlasticMac]

Good Evening Mac,

Strange, I remember there was no problem with fitting trim with boot closed.

Andy

The trim is a bit wider than the gap between the two side mouldings at the top corners, and I thought using force might bruise the trims. You have to start with the trim about 20mm away from the hatch, to line up the, (pesky), push for clips.
I'd do it my way with the hatch slightly open next time no hesitation.
Mac.

 

[PlasticMac]

I too have had same issues as @Robin_Cox , I followed same logic and had same results as you Robin. Very frustrating as the head unit is the nicest looking and I didn't want to swap it. This is a great find from @PlasticMac and no doubt will benefit a lot of fellow audio bereft drivers!!

Can the plug be replaced with a spade connector and wrapped or does it have to be the plastic plug off a donor car?

I think that by far the best solution is the connector, and short cable length from a donor.
You do need to be sure the connector is the problem first though ...
Mac.