Sounds like a fuse or relay issue. Have you carefully inspected all if the fuses and relays? Ensure they are all seated properly and not blown?

 

Thx, will check fuses and relays.

 

I am following up on a post I made a week ago about my 2004 c240, the car runs but the windows, horn, turn signals and ac does blow checked all fuses and they are in good shape, the fuses under the hood are hood but they do not show power on the volt meter. I have been told it's probably a relay but I don't know which one.

 

You can look under the fuse box covers for the relay mapping, check owner’s manual or Google search like this:

Fuse Box Diagram Mercedes-Benz C-Class (W203; 2000-2007)

Fuse box diagram (location and assignment of electrical fuses and relays) for Mercedes-Benz C-Class (C160, C180, C200, C220, C230, C240, C270, C280, C320, C350, C30, C32, C50) (W203; 2000-2007).

fuse-box.info