Film from 70s or 80s, likely crime drama.

Trying to identify a film from 70s or early 80s where a wife finds her husband stash of money from a robbery in the garage or basement. I think it’s hidden in some airconditioning ducting. She calls the police who turn up. When the husband returns home in his car he flees upon seeing the police. He then calls an acomplice who tells him to meet him somewhere and to ‘follow the signs’, meaning road signs. Its killing me trying to work it out. Movie is american. Thanks in advance.