EQSS first engineers a kit and then carefully document how best that kit should be installed (step-by-step) on specific EWPs.
Problems occur when the EQSS installation manual is not followed. In particular, the Overwatch ECU must be mounted inside the EWP control box where it cannot get wet. Furthermore, when mounting the ECU, it is imperative that it's oriented in a manner that resists water penetration (when a control box proves to not be water proof). If the ECU is allowed to get wet, it is very likely that the entire EWP will become disabled and unusable.
Below are photos of correct mounting and orientation in a range of different control boxes.
ECU and ECU cables all pointing downwards (toward the bottom of the control box).
Water is less likely to enter the ECU and even if it does, can easily run out again - as the ECU openings are facing downwards.
ECU Mounted on the control box side - sockets facing down
Not mounted facing down but instead there's an air
gap between the bottom cover and the ECU.
Mounted on the bottom panel, but the bottom panel has a tall lip all the way around for a great seal .
The cable entry point is also another critical area.
The operator sensor (LIDAR) connects via a cable and enters the control box through a gland. This gland must be tightened so that it doesn't ever become an entry point for liquids (heavy rain, pressure cleaners).