fuel station timer broke

If cleaning the contacts doesn't work, inspect the board carefully (assuming it's a printed circuit board that isn't potted in epoxy or rubber or something) for cracked or dry solder joints and reflow any that need touching up. These would mostly be around the connectors or larger/higher power components; things like SMD chips more rarely have problems, and are often somewhat trickier for the amateur to clean up. If you aren't sure of your soldering skills it might be good to get help if you find problems.