When the windshield defrost is on there is a odd bitter-sweet odor and the right side of the interior windshield actually fogs instead of defogs. Any ideas?

The defrost circuit is shorting out.....unfortunately they don't make things the way they use to, what is happening is the defog circuit is actually bare wiring strips (not dangerous) that are exposed to heat the windscreen, hence removing the dew that is caused by the moisture that is produced
as they age, they wear out, now you will find if you look closely is that the strip that is there will not be a uniformed clean strip of metal but a chalky, possibly black section where it does not clear the window and this is where you can repair it.

at your local auto shop, there should be a defog repair kit, that has a metal paste in it thayou paste on with a little brush

its an easy quick fix repair you can do on the weekend

tell me how it goes