I bought my 07 Tl-S this past august. This winter I found out quickly that the rear defroster doesnt work. I looked in the underhood fuse box. the 30a reg mini fuse is good and tested at 12v. The 40a tall box with a clear top and what looks like a old style glass fuse in it seems to be good. It has 2 prongs. I swapped it with the same looking green box fuse from a known working feature and it didnt make a difference. I probed the terminals and it shows 0v when defroster is off and only .3v when I pressed the rear defrost button. Then theres a relay in that box that I think is for the rear defrost. The fuse lid with the layout of whats what shows just a symbol for that relay and it looks like the defroster icon. Anyways it has 4 prongs, Probing it with the ground probe on my meter touching the engine. 3 of the 4 terminals show 12v without the relay in it and doesnt matter if the defroster button is pressed or not. I pulled the relay for the heater I think and it only had 2 terminals with 12v. Im not sure but reg relays should only have 2 terminals have 12v and thats only with its activated. So Im lost.

 

Here's the manual regarding defogger testing + relay testing.

 

Thanks!!