Just bought a 2001 Mazda B3000 SE (basically the Edge trim Ranger), and the previous owner had a cap over the bed. When he did that, he took off the high-mount brake light/cargo lamp fixture to make room for the cap. He took the cap off before selling it, and I bought a new light from the dealership to ensure proper spec. Super easy to install, but now that I did that, the dome light doesn't come on when the door is opened, and the dome light itself is really warm even though it's been off and sitting in the garage. I am tempted to take it back out or unplug it for now, but has anyone experienced something like this or have any idea why a true Motorcraft part would trigger something like this to happen? The lights (dome and cargo) work when you turn the dimmer switch up to the click point, and the brake light works as well. Just seems like an odd thing to happen.

 

Welcome to the forum

Just FYI the dimmer wheel uses the same fuse but different circuit to activate dome light, it by passes the interior light relay in relay box 1(above gas pedal area)

The GEM module is used to activate dome light when a door is opened and "Door ajar" light should also come on, GEM activates interior light relay when door switch is Grounded when door is open

Check ground for cargo light/3rd brake light setup, it shouldn't be sharing Dome light ground, should have a separate wire

I show black/pink stripe wire for cargo light and black for ground wire
3rd brake light uses dark green wire and uses same ground as cargo light, black wire

 

Thank you! I'm a newbie at DIY stuff beyond changing filters, so wiring is a bit intimidating. I'll check this out, though. I did notice the dome light works fine with the passenger door, so I think there might just be something wrong with the driver door switch (which was fine when I bought it just a few weeks ago). More digging to come...

 

The Ford door switches are a known issue

They are located at the bottom of the latch inside the door
So any dirt, debris and water end up IN the switch, so they stop working at all or get stuck "closed" so dome light stays on

You can try spraying WD40 into the latch and it will also run down and into the switch, and might get it working a gain.