Hmm, so u think an 09 routan has the same under dash wiring as the 87 jetta? It's only 22 yrs newer and built by 2 different companies!
Well, we haven’t redesigned the wheel in a few years. I would suspect that the relay hasn’t been redesigned either. But I’m sure that some engineer guy tried a less than round wheel to mask engine noise. 
Could be coil. A good bet is to replace relay and coil. Both are easily done and inexpensive, The alternatives are expensive,