Your vehicle has an overdrive button on the shifter maybe. When you start your vehicle, overdrive is always on. When you tow something, you want the overdrive to be off, otherwise the transmission will run hot and that will lead to bigger problems.
Normally the overdrive is allowed , so the overdrive OFF light does not light up When the overdrive is switched off , the overdrive OFF light will light up to let you know that the overdrive has been switched off
The overdrive is "ON" when the light is "OFF". Notice the light for the overdrive has a slash through it.
If the overdrive's off light is on that means it's off. If it is off then the overdrive is on.
Overdrive is the normally allowed position so you don't see the light on If you turn OFF the overdrive , the overdrive off light will light up or if there is a problem the overdrive off light will flash
Overdrive ON is the normal position But if you are towing something or driving in hilly country where the transmission is constantly shifting from overdrive to drive , then you want to switch the overdrive off
If the light says off then your overdrive is turned off, push the button again and the light will turn off and overdrive will be on again.
bad fuse or bad switch
The overdrive light will be off when the overdrive switch is pushed in. If the light flashes then that's a trouble shooting code.
overdrive off
Overdrive is the normal position - if you are in hilly areas and find the transmission keeps shifting back and forth between overdrive and drive , you can use the overdrive cancel switch to shut off the overdrive feature and if you are towing something you also want to shut off the overdrive
The overdrive off light flashing - indicates a malfunction has been detected
keep the overdrive shaft button pressed, there is a panel light called "O/D" that should light indicating the overdrive is OFF. In that case make sure the light is OFF which means overdrive is ON.