Background: I don’t have auto lights. 
Purpose: I would like auto lights (and auto wipers and coming home lights that’d come with it). 
Issue: though I reckon I could give the hardware side of things a good go, I don’t have coding on my side. Therefore any help would be hugely appreciated. 
 

Looking at the Auto Switch p/n - 5GG941431D

Rain/light/humidity sensor - 8U0955559C

Both from AliExpress, and would need the additional cable from the switch to the control unit. 
Anyone got tips for routing the cable too? It’d need to be extended but that’s no real issue as I’ve a soldering iron/heat shrink/etc. 
 

Diolch in advance! 
 

edit: this is for a ‘68 Facelift SE Estate.  

Edited 26 July, 20205 yr by Benz3ne

Auto switch purchased from a UK seller for £12. Looked scuffed in the pics but has arrived in v. good condition. Have installed it prematurely just so I know where it is. 🤣 Turning onto 'auto' doesn't trigger a warning but instead just puts on the dipped headlights.

8U0955559C sensor I'm debating spending an extra £15 on to get from UK instead of China for speed of delivery... 

As for the cable to run between the switch and BCM, does anyone know the approximate length of this? I've seen links to some where people have extended it by soldering additional wire in but I've not seen how much wire goes in...

Diolch yn fawr - thanks a lot!

Update: That escalated quickly. A used, tested one from an Audi something-or-other with the same part number for the sensor on eBay came to my attention.

Purchased for £25, same price to get one from China.

Should be here in the next couple of days.

This retro is quite simple, but the mounting of the RLHS on the screen is going to be a challenging without the correct windscreen but not impossible. All you’ll need to do if you have the humidity sensor is replace that with the RLHS, add the Auto trigger wire from Pin 2 of the light switch to Pin 16 Connector C of the BCM. Give yourself about 2 meters of cable and you’ll be fine. Coding wise there won’t be coding for auto lights and wipers per say, but there is coding to do if you want to disable the auto wiping in the radio menu and coding for CH/LH lights which I can help you with. I can send you a scan of my car that has it active. I have an FL BCM in my car so it’ll match up but mine is a High model and the SE is likely to be the Mid one so I’ll have more options but the coding relevant to the Comfort Illumination will be the same.

27 minutes ago, SashaGrace said:

This retro is quite simple, but the mounting of the RLHS on the screen is going to be a challenging without the correct windscreen but not impossible. All you’ll need to do if you have the humidity sensor is replace that with the RLHS, add the Auto trigger wire from Pin 2 of the light switch to Pin 16 Connector C of the BCM. Give yourself about 2 meters of cable and you’ll be fine. Coding wise there won’t be coding for auto lights and wipers per say, but there is coding to do if you want to disable the auto wiping in the radio menu and coding for CH/LH lights which I can help you with. I can send you a scan of my car that has it active. I have an FL BCM in my car so it’ll match up but mine is a High model and the SE is likely to be the Mid one so I’ll have more options but the coding relevant to the Comfort Illumination will be the same.

Diolch yn fawr, Sasha, ti’n seren! 
I have the humidity sensor so hopefully it won’t be a pain to install the new sensor! 
Good to know also re: coding and what is/isn’t required.  I’ll definitely revisit that in due course but right now I don’t have anything to code with (eyeing up OBDEleven) so can sort the coding thereafter. 

Sensor received, cleaned with isopropyl alcohol and installed with the help of an immensely thorough video. 
Tested the auto wiper function and it works! It seems reasonably keen to wipe when wet so I’ll be tinkering around with the sensitivity on the stalk next time it rains here (which shouldn’t be that far away, really). 
Just waiting on the pins so I can draw up a length of cable and route that hopefully this weekend! Then it’s auto lights in the bag too (hopefully)! 
Any idea whether there’d be a fault or similar for the humidity sensor that I could check quickly without VCDS just to make sure the sensor is tip-top? 
 

Aaaand the useful video:

 

Edited 6 August, 20205 yr by Benz3ne

Right so I have pins which I've crimped to either side of a circa 2m-long 1mm single-core cable.

I can access the connector behind the auto-lights switch, which I've put in place for the time being.

I've no doubt I can access the BCM, but what is the best way to route the cable from one to the other? Are there any other bits of trim that need to be removed (I'm thinking from driver's side)?

Cheers in advance!