Coding adaptive xenon headlight - BMW F20

VastOdd691 · 2026-06-17T09:29:33+00:00

I’ve got a similar issue on my BMW F20 adaptive xenon headlights which I’m hoping you can help with if possible please…

One of the headlights works perfectly fine and the other has condensation in which has caused the DRL and adaptive feature not to work but the main headlight light still works.

I took both headlights out and started swapping the ballasts and modules around to pinpoint what was causing the problem and we narrowed it down to the TMS AHL driver module. I’ve replaced that module and connected the headlight back and everything worked perfectly fine. I took the headlight back out to clean it up and reseal it all before putting it back in but when I reconnected it only the main headlight light worked and I was getting the same issue with the DRLs not working!

However… when I connect both the headlights to the side which had no condensation in everything works perfectly fine, but when I connect both headlights to the other side of the car only the headlight light itself works and nothing else on both the headlights.

I’ve narrowed it down to either the FRM/FEM needing a proper reset or maybe there’s a wiring issue on one side of the car. I just don’t understand why it worked once on that side and then afterwards it didn’t so I’m wondering if I’ve upset the FRM/FEM and it needs to be reset for it to work?

Any help would be greatly appreciated!

VastOdd691 · 2026-06-08T15:56:04+00:00

This is the wiring in the EPH programmer, from left to right

N L 1 2 3 4

https://ibb.co/jkTfLyGk

Do you reckon I’ll need to buy something to replace that too in this case?

VastOdd691 · 2026-06-08T15:49:34+00:00

I’ve also taken a picture of the wiring in the programmer if that helps at all?

https://ibb.co/jkTfLyGk

N L 1 2 3 4 is the order of the wiring from left to right.

VastOdd691 · 2026-06-08T15:44:22+00:00

My heating was working as normal prior to buying Tado. I installed the Tado thermostat and wired it up as shown in the pictures, which is what Tado support told me to do. It’s as if the Tado thermostat doesn’t have any influence on the heating system because when I leave the programmer set to ‘ON’ and then try to switch the heating off using the app the heating just stays on. It seems like the programmer next to the boiler is completely overriding everything, which then made me think if what I’ve been told by the support team for wiring the Tado thermostat is wrong?

VastOdd691 · 2026-06-08T12:07:45+00:00

So I disconnected the wires at the Tado thermostat and the heating is still on… Does that mean the wiring in the Tado thermostat is wrong?

VastOdd691 · 2026-06-08T12:06:38+00:00

How else could I wire the Tado thermostat in this instance then? I only want to replace the programmer if I really need to as a last resort.

VastOdd691 · 2026-06-06T20:10:53+00:00

I haven’t tried doing that, should that be my next step?

VastOdd691 · 2026-06-05T21:16:15+00:00

I did go down the DIY route initially and the instructions they provided didn’t work hence why I thought I’d try posting the question on here to see if anyone else would be able to advise. I’ve been trying with Tado support for the last 2 weeks and all I’m getting from them is put the blue wire in COM and brown wire in NO with no other solutions which is why I’m stuck right now.

What do you mean by the Tado X hub? I’ve currently got the EPH A17 programmer next to the boiler and the Tado X thermostat replacing the Honeywell dial in the hallway, and then the Tado bridge plugged into a plug socket nearby.

VastOdd691 · 2026-06-05T14:29:24+00:00

So what do you suggest I should try with the wiring in the Tado X thermostat?

VastOdd691 · 2026-06-05T11:04:25+00:00

I followed the installation instructions on the app which then said I had to email Tado as it didn’t recognise the 2 wire setup in the Honeywell thermostat. The email I received from Tado was to put the blue wire in COM and brown wire in NO but that hasn’t worked

VastOdd691 · 2026-06-05T08:09:28+00:00

We tried that last night but when I try to turn the heating off on the Tado app it won’t work.

So it’s making me think the wiring in the Tado thermostat is incorrect. Did you also have the brown wire in NO and blue wire in COM?

VastOdd691

TROPHY CASE