Back up lights

[JackEnloe]

I have a 2004 National Tropical, Freightliner Chasis. My back up lights do not work. I have checked the bulbs and they are fine. Have checked the plugs ins for the bulbs nd there is not any voltage.
Does anyone know where the switch or selinod might be for activating the back up lights?
Thannks for your help.
Jack

[JackEnloe]

I wll check on that. Thank you for the tip.
jack

[othertonka]

The backup switch should be on the transmission itself. Get underneath and look for a round switch with at least two wires coming out of it. Pull the plug off and check for it to have 12 volts at one of the wires. If you have voltage use a jumper wire to the other wire and see if the lights come on. Hint, might have to have the ignition switch ON to test.