Replacement screen about 18 months ago, has worked same as original, clearing screen quickly leaving a thin central strip and wider wedge shaped areas at each side. Last winter it didn't get much use, but all seemed OK.

Couple of weeks back, screen misted, not frozen. Used the front screen button and the LHS cleared quickly as normal, RHS (driver's) did not. Ah begger I thought.

Checked all fuses, OK, took fuses out, checked continuity, voltage, all seemed OK to me. Gave it a good Basil Fawlty threatening, and left it at that.

Next time used it was a hard frost, pressed the prog button, which switches front and back on and sets the blower blasting away, screen cleared, both sides clearing at same rate. As usual the areas where the wires embedded clearing first.

That's been the case twice since.

Now again screen misted, not frozen, pressed front screen button, LHS cleared MUCH faster than RHS. Areas without the embedded wires not clearing, so clearly (haha) something is working.

Confused. Could it just be crappy contacts that need cleaning on one side? If so, why do both sides work the same on PROG setting?

Heated front screen is primarily designed to defrost exterior not demist interior. Program to demist. All FL2's (3) Gone
2011 Mercedes C180 CGI Gone
FL2 GS Auto SD with heated leather, factory tints, alloy spare and a few other bits.