1990 CS rear defrost wire?

[Justin]

I'm having some trouble locating the wire from the electronic climate control to the rear grid. I'd like to hook a friend's remote start into the rear defrost if possible. Anyone know offhand what it is? For all I know it's part of the solid state in the climate control, but there has to be some way to do it.

[Brian P]

it's purple, I know that much. Let me check my book.