Technical Seicento Headlight Beam Adjuster Motor

[Drill bit]

I have a 02 Seicento. The right headlight was pointing at the ground. I went to adjust it. It would not adjust but the left one would. I tried the headlight beam leveler switch on the dash. The left beam adjusted; the right did not. I heard no noise from the right motor. I took out the right headlight adjuster motor. The rod going into the headlight had deteriorated (apparently a common problem) and had been creatively fixed with small cable ties. There were three wires going into the connector; black, yellow and green. I went to test them with my test light. The green wire is hot all the time regardless of whether the beam leveler switch is turned or not. I thought the yellow wire would go hot when I would turn the headlight beam leveler switch on the dash but it didn’t. I don’t know much about electrics but I thought the yellow wire would go hot to activate the motor. I don’t want to take the part off the left side and put it on the right because it might be in poor condition and that might break it. I am in Ireland and I might have trouble getting one new part never mind two. What does the yellow wire do?