I need to see the headlight wire harness diagram for a 2007 Yukon Denali 6.2L.... My passenger low beam isn't working....

If front park lights are working highly unlikely headlight switch is the issue. Is the vehicle equipped with a trailer towing package and wiring to the rear? I would start there. This vehicle may also have a taillight module located under the vehicle on the passenger rear attached in the wheel well area that goes bad

Remove plug from light bulb, using 12 volt test light hook up ground to negative side of battery,then touch probe on positive terminal to make sure test light is functional.next- turn lights on and then probe the plug at each terminal- there should be one wire that has power and the test light should light up. If the test light lights up then you need to test the circuit ground for the wiring harness. So remove the test light clamp and put it on the positive post of the battery. Now retest the test light by touching the probe on the negative post on the battery and the test light should light up. Next with the headlights off-probe the other terminals and if there is a good ground in the harness the light will light up- if not then there is an open condition in the headlight harness- a broken wire or a bad system ground.If both tests are performed and either condition does not happen then a wiring schematic will be needed to perform the repair. This is after all fuses are presumed good.

Odds are you have a connection problem. Stop & buy a tube of dielectric compound from an auto parts store. Apply it to the electrical connection at the lamp after you make sure there is no corrosion present.

open your hood and it should be right behind where the light is you will have to twist it and pull it out there is only one light for the low/high beams

Narva RangePower +50 and GE Nighthawk are supposed to be about the best. Stay away from the Sylvania Silver Stars - they are a joke.

i would try replacing those bulbs,the headlights are dual filiment and can work on just high beam and not on low beam,so start there and replace your bulbs

Change the bulb. High and low beams are separate bulbs located in the headlight housing. Im not sure on the 07 but the earlier design Yukon (02)you have to pull out a pin located under the hood on the top of the light housing in order to remove it.

Power for the headlights on the Left side (High and low beam.) comes from the same fuse... The ORANGE wire and the ORANGE/BLACK are the same, they connect in the harness. If you only lack the 12v to make the light work connect them at the headlight assembly.

If your low beam also lacks ground the Left low beam ground is shared with the right low beam ground... Run a wire from left low beam DARK BLUE to right low beam DARK BLUE/WHITE.

If its not working now then your cursed, seek a witch doctor.

Hi,
The simple answer may be that the low beam side is burnt out. Replace the bulb.
However, if both headlights have stopped working when switching to low beams, there may be a problem with the relay or the switch itself. If the cost of a relay is low for your car, it may be less expensive to simply replace that component than to have it diagnosed in a repair shop. Replacement of the switch requires some disassembly of the steering column or dash in most vehicles.
This is how to fix the low beam..
1.Check your fuses. The plastic panel covering the fuses should have a diagram detailing what each fuse covers. If yours is missing, or unlabeled, check your owner's manual, or a Hanes(tm) or Chilton(tm) repair manual. Often if a headlight is not working, it is the result of a blown fuse. Fuses have a wire running through them that will melt when too much current is run through them. If the fuse is blown, the wire will be broken. If the fuse for the headlight you are working on has an intact wire, it is likely the problem lies elsewhere.
2.Swap the headlight for its twin. If your left headlight does not work, put the light from your right headlight in its place. If it works with the other headlight in place, your headlight bulb is dead, and needs to be replaced.
3.If this does not work, try using a voltmeter on the plug for the bad headlight. Turn on the ignition, and turn the headlight switch. If the voltmeter shows no current, then either your switch or the wiring leading to the headlight has gone bad.
4.If replacing your headlight switch does not solve the problem, then there is a break in the wiring leading to the headlight, and the wiring will need to be replaced.
Thanks for contacting fixya.com

check out the dimmer switch.does cruise,blinkers ,and wipers still work right.if they are all on same switch.