HID driver side headlight will come on when ignition and switch are off

Hi,

The only thing I see that can be causing it would be related to the auto light sensor in the body control module. When it turns on, do you know if it is high or low beam?

If you look at the attached pic, you'll see that the switch goes to the BCM and then it goes through the sensor (on automatic) or the sensor is bypassed and power sent to the lights. So, pay attention to which beam is turning on and try pulling the appropriate fuse to see if the light goes out. If it doesn't, then suspect a short to power in that wiring to the light. If it goes out, I have a feeling it is with the BCM.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know.

Joe

It is the low beam that comes on, I will work through your suggestion and see what I find. Thank you.

You are welcome Jon. I will watch for your reply.

Take care,
Joe

Hi Joe. Okay, so I pulled the fuse #35 in the PDB which is the "High-intensity discharge headlamps driver side" and the headlamp went out. Although now I see there are low-beam and high beam fuses inside the cab. I will look to pull them and see if I get the same result. Thoughts? Thanks so much. Jon

Yep, there are several. Try them and let me know the results. I'm just trying to determine if there is a short to power after the fuse.

Joe

Hi Joe. Okay, pulled the low and high beam fuse in the cabin and headlamp still remained on with fuse pulled (low beam is on but pulled high beam just to be sure). It still goes off after I pull the fuse in the power distribution box in the engine compartment though. Thank you for helping me trouble shoot this. JH

Okay, then we have a short to power after the low beam fuse. If I had to guess, it is going to deal with the shutter solenoid. I'm thinking through this and want you to confirm there is a ground to the solenoid. If that has failed, it may be back feeding power to the low beam. Please understand this is a theory at this point.

I attached a pic below and highlighted the wire and indicated the location. You are looking for a black wire with a green tracer

Let me know what you find.

Joe