Rear defrost issue

I have a 1968 G with the rear defrost which spines freely but nothing when hooked up to 12 Volts. Any clue who repairs them and if so I also need the cover? I do know someone with a NOS new but $500.00 plus shipping. Thank You

Good working used ones with grille show up on eBay for $125. The switches and brackets and knobs are harder to find and more expensive.