There are 2 spring-retainer clips at the bottom of the unit. After removing the top 2 screws it is a firm tug upward at a 45-degree angle. Removing the plug also helps since there's usually not a lot of slack in the cable. It is possible to reach around on the passenger side of the module and pinch/push the clip from the back/bottom of the unit, but the driver side is more difficult to do without a tool. It does take some force to get it out and you might damage the spring clip in the process.