need info on dome light independency.

I have a center dome/cargo light, two wires, yellow and white. It is a 1993 Chevy G-Van, all negative door triggers, all new LED fixtures. I need to illuminate the center dome/cargo light only, with a switch. It has to work independently of the door triggers. I can get it to work with a door open, and the dash dome supervision switch off. If I leave the switch on, and exit the vehicle with the dash switch on the dome stays on. If I turn the switch off at the dash, it doesn't work with the door closed. I currently have IGN +12 to a switch that I need, then to an an anterior camera and monitor, and the yellow wire on the center dome with a diode. I want only the that dome light to come on with the camera and monitor. I usually get it, but I am just missing something. I will probably need relays too. I drew up a diagram with a relay, it still didn't work right. Thanks.

All I can tell you is that the yellow wire is the constant power source, and the white wire goes to your pinswitches and also to the light switch mounted on the dash. If you want to use a separate switch to control it, use a Single Pole Double Throw On-Off-On type switch. Connect the constant wire to one side of the bulb. Connect the other side of the bulb to the center terminal of the switch. Connect the white wire to one end of the switch. Ground a wire and connect it to the other end of the switch. Switch in the center is off, the light will never light up. Switch in one position will illuminate the light anytime, regardless of the position of the doors. Switch in the other position will light the bulb when either of the doors are open.

The site I use for wiring diagrams doesn't have any listings for interior lights for 1993. Closest I could find was 1998. Domestic GM's, particularly light trucks/vans have used wht and orange at domelights for decades. orange = hot at all times, and wht = (-)trigger. Your "yellow wire" at the dome light is confusing me. Unless its a pigtail in like a roof console harness that goes to a connector that becomes orange on the body side of the connector. Yeah, that may be it. when in doubt, Test. One side (yellow) should be hot at all times. The white probably goes to the door and dash switches. Assuming the light has power at all times on one leg (yellow) use a relay for your project. 85 to ground. 86 to your (+) source. 30 to the white wire domelight side. 87a white wire from body side. 87 to ground. When your input (camera) trigger is off, the domelight works normally. When your trigger is on, the domelight is switched on by connecting it's white wire to ground. That should get you thinking again. Test for the yellow wire being hot at all times. I'll bet it is.

I figured most of that, but you got to be careful that grounding the white wire there, doesn't turn all the lights on. The door pins, when you open a door, ground. Any open door turns all the lights on, I do no think the door pins are isolated, but they can be with diodes.   I will give these methods a try. I did try the relay thing already, and it didn't work, may have been wired wrong. The owner said two to wire with the relay, with his info; I will verify his with the one above. Thanks for all the help, will give them a go...

powerslave wrote: I figured most of that, but you got to be careful that grounding the white wire there, doesn't turn all the lights on.

That's why my suggestion cuts the white wire at the target dome light in two. The wire towards the pin switches and other lights is never grounded by the relay. When relay coil is energized, the dome light white wire (30) is grounded (87), but the pinswitch white wire (87a) is not connected to anything. When relay coil is de energized, dome light wire (30) is connected to pin switches (87a) and dome light behaves normally.

This worked just fine. Also, I needed to add another Relay to clip the 12+ to the LED when you put it into Reverse. That was easy. This project was to add a camera inside the Van, top center console looking down on the customer's Dogs. She has show dogs, horses, and so on. The light is to turn on with the Camera (rocker in console), then turn off if in reverse. We put a 7" LCD switching monitor too, so if she was looking at the dogs, shifting in reverse cut the feed to the light, and switched to input#1 on the monitor for the rear camera. Everything worked out great. Been doing a lot of jobs with Relays lately. On to adding a Timer for an Aux. water pump in a Gen2 Viper, that will run for 2 minutes at key-off.