Might seem like a silly question, have you checked to see if they both come on in reverse? If the Arona is like the Leon, they should do.
Are the foglights LED or halogen bulbs on your OH's car?
On LED or halogen cornering lights, I always think it's asking for trouble to code cornering lights on halogen bulbs since atleast on the
Ateca they are very difficult to get at to replace. LED ones are a different story.
Cornering lights are a bit of a fad by region. The Spanish love them.
For those with Obdeleven the mod is listed for the FR:
ACCESS CODES C.U. 01 (Engine): 27971 C.U. 03 (Brake): 40168 C.U. 09 (Central Electrics): 31347 C.U. 13 (Adaptive Cruise Control): 20103 C.U. 17 (Dashboard): 25327, 47115 C
forum.obdeleven.com
Activation Cornering light + Adjusting parameters Cornering light (LED lights)
1. Control Unit 09 (Central Electrics)
2. Adaptation
3. Static AFS light
- Vorschrift
New value : FMVSS_517_108
Old value : off
- Untere_Geschwindigkeitsschwelle
New value : 0
- Obere_Geschwindigkeitsschwelle
New value : 125
Old value : 40
- Steering wheel angle, offset
New value : 0
- Unterer_Lenkradwinkel
New value : 30
- Oberer_Lenkradwinkel
New value : 30
4. Leuchte12NL LB40
- Light_Function_B_12
New value : Abbiegelicht links
Old value : nicht aktiv
5. Leuchte13NL RB3
- Light_Function_B_13
New value : Abbiegelicht rechts
Old value : nicht aktiv
Saying this that's for the FR Led version above. The lighting units Led / Halogen are specific, those Leuchte values in 4 and 5. Will be a different code for halogen.
Any one excited enough can study theirs. Gives something to go on. Interesting to see how it's done.