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Afternoon guys, not really posted much but have "lurked' for some time. Bought my plus about 6 months ago and all has been well, you might be familiar with it, formally owned by Gav66 and PHIL T. Just reading back on the forum i can get a taste of its history and issues on top of the paperwork.
Anyway, got in it the other day and the head unit is "dead'. Have checked fuse by drivers door and on back of unit but they are fine, are there any more? Not sure which wire is the live to the unit so not put a multimeter on it. Everything else seems fine, no flat batteries or jumpstarts, it had just been sitting plugged into charger for a couple of weeks. Not checked codes as i have misplaced the charger for the VCDS laptop.

Was it a retrofit RNS-E? If so that might complicate things a bit depending on how it was wired when it was put in. Can you see if it's got a Kufatec adapter on it?

Check to see if you can power the unit directly on the bench. There are plenty of pinouts floating around. I think it's even marked on the back of the unit what the permanent and switched 12V is.

I think there's a connector under the carpet that can corrode if water gets in, so check for damp under the soundproofing.

Thanks for the reply. As far as i am aware it is standard, car is a plus (Jul 04). Was hoping i had missed a fuse, will put a live to the unit and see if it fires up. I had read about the corrosion under the carpet so will check that if all else fails, its under passenger seat somewhere isn't it? I know it had leaks fixed both sides at some point, its amazing what you can find out about a car by checking back on previous owners posts. It has however never seen the rain and lived under cover during my ownership.

viewtopic.php?f=9&t=134413

The options Sticker in the spare wheel well will tell you if it had an RNS-E as standard or not.

Thanks for that link, wiring at the back of unit all looks standard, only thing i have changed is added XCARLINK but that was a few months ago and that worked fine. I have tried removing that but makes no difference. Car is in a lock up that i can't access Sun afternoon so will have a look tomorrow. I assume the seat is easy enough to remove, looked ok on that link. Don't want to trash the natural leather seats by triggering an air bag or something.

Before you do that, see if you've got 12V getting to the unit. There's only one fuse upstream of the unit, as far as I can tell from the electrical diagrams.

It's coming back to me now... the RNS-E doesn't have a connector from the ignition. To turn on, it requires a CAN message from the car.

See if you can connect to the RNS-E with the Vagcom. I think there's a way of rebooting it from the Vagcom if so.

You could try a reset from the buttons on the front. Apparently you can hold down "radio" and "setup" simultaneously for 10 seconds or so and that will reboot the unit.

You could also try holding the power button down for a while. Sometimes that resets stuff.

Brilliant, thanks for your help. Will get on it tomorrow and check for 12v at unit. Checked at fuse box yesterday and the fuse holder had 12v and fuse was good. Have just found laptop charger so that is on charge so VCDS is good.

Tested the input and it was a bit odd, sound 10v. So thought i would check the wires under the seat, couldn't get the bloody seat out! followed a couple of online guides, rear caps off then undo the bolts at the front. It was still solid so i moved it forward as far as it would go and cut the carpet a little right under the seat and out of sight.All the wiring perfect and dry, except for the bundle that seems to cause problems. It is a complete bodge under there, 5 wires crimped together with a little rubber hat on top. Hopefully the picture has uploaded but that's the remains of the joint. Anyway, just to test things i bundled them together with tape and tried it. Everything back to normal!
Just need to work out a permanent way to connect them, a Waco block would do it but will try and think of something better. I would suggest that people check this joint if they get a chance as it looks like a ticking time bomb.
Thanks for your suggestions Shop, right again!
I have checked the Sticker to see if the RNS-E was original but couldn't make head nor tail of the codes, what am i looking for? Not sure i should put a screenshot of it online as it has everything on it.

Wow. What a mess! Hard to believe that’s an OE fitting.

I personally would solder them and use heat shrink to insulate. I don’t really like mechanical connectors for multi core cables. Having said that, those Wago connectors with the little lever are ace and they would be better than chewing gum.

Doesn’t really matter about the options codes now. You’ve found the problem.

Actually you could post a pic of the Sticker without the VIN if you want me to decode the options. The vin is the only potentially sensitive bit, and even then, not particularly.

Or send it to me by PM. Whatever.

Sorry for late reply, been out for evening.
Funnily enough there was another a couple of inches away and that's fine. It was dry and almost seemed like galvanic corrosion that you get on boats. My mate has a VW California and that is corroding on the roof, apparently its due to all the electrics and the alloy roof is acting as an expensive sacrificial anode.

Oh, you've got a Plus. Nice. All Plusses had RNS-E as standard.

The RNS-E replaced the RNS-D on all models towards the end of the production run. Maybe that explains the "bodge" as relatively few cars had it.

Anyway, the relevant option code is 7Q2.

Nobbsy wrote: ↑

Sun Dec 10, 2023 2:45 pm

car is a plus (Jul 04).

Maybe I should learn to read better.

Thanks again Shop.
If anyone is interested in checking theirs the wires are a couple of inches below the seat belt bolt on passenger side transmission tunnel under the seat.