What should you do if the green OK TO PUMP light is not on after engaging the pump?

If the green "OK TO PUMP" light is not illuminated after engaging the pump, the best course of action is to shift the transmission into reverse and then back into the pump gear. This action can help reset the conditions necessary for the pump to function. In many emergency vehicles, shifting gears can sometimes engage or reset various systems within the vehicle, ensuring proper operation.

The scenarios leading to the light not being on could include transmission issues or the pump not fully engaging in pump mode. By cycling through the gears, you often re-establish the connection needed for the indicator system to recognize that the pump is engaged and ready for operation.

Addressing other options provides insight into why they may not be the best initial steps. For instance, re-engaging the parking brake may not contribute to resolving the issue since the brake typically does not impact the engagement of the pump. Checking for leaks is important for maintenance and safety but does not directly address the immediate concern of the pump's operational status. Turning off and restarting the pump is a useful troubleshooting step in some cases but may be more time-consuming and does not address the possibility of simple gear engagement resolving the issue.