Rear window defrost

[rcman]

only a few of the lines running across the window seem to get warm. any help?

[Donald]

There is a repair kit that you can get at the auto parts stores.
In the kit there is a conductive paint that you apply to broken/damaged areas of the strips (lines).

Sometimes the broken areas are very obvious, but sometimes you need to look at the strips with a magnifying glass to see where it is broken.

Those strips are usually damaged by objects resting against the glass, or when you try to remove tint film.