The reason I asked for mileage is that it seems from past
posts that 70K miles seems to be the window where many harnesses go south.

This is not an exact statistic nor a technician talking here.
Just an anecdote.

My C280 has 33K.

The head gasket was another issue with this model.

Talk to other dealer reps and take it to another city if need be!!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD