rear defroster

i got my car removed the tint and my rear defroster button doesn’t click in i hold it down and nothing happens. I never tested out the defroster prior to this. suggestions? my car is currently at the shop for something else is it something i can fix myself cause im broke.

The rear window defog is controlled by the ICU, ICU problems are common on G2s and older Honda/Acura. 94