Hi I have a question regarding my interior dome light. I replaced both door switches and have the dome light on the door setting and it only dims instead of going off when doors are closed? Can I fix this myself and what do I need to do to fix it?
Your ability to fix the problem is only limited to your skills and knowledge. If you are comfortable using a multi-meter this should be a home fix. Understanding how the circuit works and then repairing or replacing the issue component. Fortunately for us the circuit is small with few components. We have 1 wiring harness, 3 switches, one fuse and a dome light.
Most Likely Cause
Faulty Dome Switch
How to Diagnose the Dome Light
We know your fuse is good so we can skip that. We know the bulb is good. You replaced the door switches and DO see the light dim when the door is shut. The light is however staying on as you stated. So we know battery positive is getting tot he bulb on the RED/GRN wire. Next we will need to determine where the Dome light is picking up the battery negative feed. Check the RED/BLK wire. No Battery negative should be seen when the doors are closed. Battery negative should be seen when doors are open. This means the door switches are working properly. So we are left with the Dome Light Switch and a wiring harness.
The BLK wire should be battery negative at all times. The dome switch should only see the battery negative on the BLK wire when it is switched to the “ON” position. If the dome light bulb is receiving battery negative from the BLK wire when the switch is in the “OFF” or “DOOR” position the switch may be faulty. Replace the dome light switch. If this is not the case then you are left with tracing the wiring harness and looking for a short.
1999 Nissan Frontier Dome Light Wiring Diagram