Ram 2500 domelight wiring question

[diymirage]

I have a crewcab 2500
The kids like having the rear dome on so I replaced the stocker with one from a higher trim level that has a switch in it

Run a keyed hot to it and done, right?

One my truck there was a ground on the left post, and a switched hot on the center (that on gets power when I upen the doors, or hit the button on the dash
The third post was empty, and goes to the switch inside the dome light

So, I added a keyed hot to post 3 and boon, let there be light

I open the door, it comes on, I press the button in the dome light, it comes on...and so do the front dome lights

Not what I wanted

Any idea what I did wrong...and how to fix it ?

 

[Bobzilla]

What model year is this truck?

 

[diymirage]

What model year is this truck?

2017

 

[diymirage]

Figured it out !

It was backfeeding through the middle (powered on when door open) post

Put a resistor in and all is well

(This is just to test it, everything will be connected much neater)

 

[Bobzilla]

Would a diode be a better choice to prevent that backfeed?
Glad you got it narrowed down. I was going to look for wiring diagram this morning.

 

[diymirage]

Would a diode be a better choice to prevent that backfeed?
Glad you got it narrowed down. I was going to look for wiring diagram this morning.

you're right, i got the terminology wrong

i looked up the receipt (there were left over from a different project) and it is a schottky diode i used

if i remember correctly i bought them when i hooked up a back up camera too my old plowtruck, as well as some extra bright spotlights

i wanted the camera and the spotlights to come on by separate switches, but i also wanted both of them to come on when shifting in reverse

i think the way i first wired it, was very similar to the issue i had with the dome light, id flick one switch and everything would come on
then if i shifted into reverse, the camera would go haywire due to too it getting power from different sources

so i ordered a few of these and that fixed everything