It has become very obvious that Mercedes has a batch of vehicles out there with defective defroster wires.
Let me clarify that. The wires may be completely intact and working but the problem occurs when anyone
touches the wires, such as cleaning the rear window, taping a temp tag to the glass or tinting process.
I believe that there is some final step to cure the wires to the glass during manufacturing that was skipped
or done wrong. The pic on the right below is a 2018 E class, we tinted the glass and then realizing that some of the wires
were messed up, we pulled the film back off the window while wet (2 min after install). All the wires came off the glass.
We sent the customer to the dealer and they replaced the window under warranty.
Yesterday we did a removal on a 2015 E class wagon and as we steamed the rear film off, many of the wires
simply pulled off with the film.
This morning as we were prepping a 2015 E class for tint we pulled the temp tag off the glass using our fingers
and the scotch tape pulled the defrost wires off. The second pic shows the temp tag from this morning, (look closely at the tape).
Clearly this should not happen and the fact that all have been E class Mercedes is telling.