Dome light with switch question


So my Sprinter has a dome light with an on off switch located at the very rrar of the vehicle which is great for when you are in bed. I would like to add the same type of switch closer to the middle of the vehicle. I took it out yesterday to look at it and noticed it has a connector with 3 wires. Then I took out one of the other dome lights without the switch and it only has 2 wires. Is the 3rd wire some sort of constant power or is it some sort of other kind of wire to a relay?

If I push the light button located in the overhead console it will turn it all back off even if I have them switched on. Any idea? I will take pictures tonight.


Active member
I believe the 3 wire rear switch has constant power on one leg like you were thinking. You could install a DTDT switch like the ones I installed in my ceiling panels and power the 2 wire lights while the vehicle is off. I would also install a new switch on the rear so you can feed that light from the house battery instead of the starting battery when camping.