Now that it is getting colder here in New England, it is sometimes necessary to turn on the defrosters in the morning and warm up the car. During the times that I had done this, I noticed that the rear defroster seems to be not doing it's job while parked. However, as soon as I drive off, the lines (where the wires are) start to show .

This doesn't seem to be normal. Has anyone experienced this ?

 

it takes a bit of time for them to warm up. note that a car warms up, in general, faster when you are moving.

Its better to drive and keep the RPMs low than to just sit and waste gas. That said let it idle about a minute or two anyway to get oil flowing where it needs to flow.

 

RPMs, oil and rear defroster.... is there a correlation (I'm sorry if I'm not getting you)

The side mirror defrosters already cleared up the frost/mist on side mirrors and there's still no indication that the rear defrosters are even on (just using for comparison).