Last summer I trimmed the cedar hedges, and now they are dying half way up. Im assuming I trimmed to far in. Is there a way to bring them back. Here are some pictures.
They're arborvitae (Thuja occidentalis), not cedars (Cedrus); I've edited the title accordingly. Yes, unfortunately you're right, cutting back too hard into the old wood, which doesn't regrow - there's no way to 'bring them back'. So your best option is to remove them and replant some new hedge plants. If you want to avoid this risk again, best to plant something like yew that will regrow if cut back hard.
