Need Help-No Overhead Lights at All- 2006 VUE V6 AWD

[joshjani]

My next issue that needs solving with my new-to-us VUE is the overhead dome, map and liftgate lights. They don't work at all.

Far2Grumpy was kind enough to send me a picture of the VUE wiring diagram (which I don't understand!) and a suggestion to check that voltage is getting from the BCM to the fuse panel.

Without disassembling the center console, I thought if I just pull the INT LTS fuse in the interior panel, I could probe that location with a multimeter. So I did that, and my multimeter gave a reading of -11.63 or something like that.

You might guess that I don't really know what I'm doing with a multimeter either, and you'd be right. Trying to learn as I go.

Anyway, Grumpy's notes also suggested where the ground points are, and one is in the jack compartment. So I looked in there, found a black box screwed to the chassis. It looked clean and solid, no corrosion or anything, so I left it alone.

Can anyone with a similar experience- that is, NO overhead lights whatsoever- chime in and help me figure out what troubleshooting they did to solve it? I really don't want to spend money on an electrical shop, though I think that'd be easiest and best, given my lack of knowledge! Just hoping for a magic trick from one of you all that might benefit me before I go that route. Thanks!

[joshjani]

As I'm trying to fix my overhead lights, I am wondering where the liftgate door switch is? The side door switches are obvious...but I can't see any switches in the liftgate. How does the VUE know when its hatch is open? And furthermore, could a messed up switch back there affect the rest of the overhead lights?

[fdryer]

1-Did you check every fuse in all the fuse panels? This is the first step as fused power goes everywhere. Only one fuse or two may blow to disable interior lighting. As a general guideline, lighting is controlled by the bcm and the bcm may have more than one fuse. Some interior lights aren't straight 12 volts - a digital signal operates each bulb as if 12 volts were applied. To the naked eye, lights are either on or off but a video with matching frame rates as the digital signal will reveal the lights are flickering at high speed.

2-Is there any evidence of wiring modifications inside, around fuse panels and wire harnesses to suggest aftermarket electronics was added and removed prior to selling the car? Sometimes diyers may not use factory wiring diagrams and plunge into wiring. This can result in disabling circuits or damage electronics (bcm). Most GM service manuals warn techs to be aware of aftermarket electronics incorrectly wired into existing harnesses that may cause damage. Cutting and splicing into wire harnesses while not aware of digital voltages are different from regular analog voltages may interfere with electronics with the worse case scenario of damaging them. The bcm controls many things the engine computer doesn't. The airbag and abs have their own electronics. Mechanics at the dealer level cannot just be knowledgeable about mechanical things like brakes, suspension, and body panels. More electronics in our vehicles requires advanced technical skills in electronics and basic computer systems.

3-Something about your descriptions of loss of interior lighting suggests either a ground connection is common to this problem or wiring issue. If a wiring issue then possibly the previous owner inadvertently modified wiring for aftermarket electronics or maybe simply leaving a connection partially connected somewhere. This would require looking everywhere inside, starting from either the lighting connection or the fuse panel side. Partial connections may or may not be obvious so a hands on approach is needed to ensure all plugs are connected correctly. You may have to remove panels and fascia, pull out the radio to see where wire harnesses go. An exploratory venture to find anything unusual. All factory wiring harnesses are bundled, taped, and fastened securely against vibration where chafing won't wear down insulation and create a short circuit condition as bare wires contact sharp metal edges that provide electrical ground.

There are two way to check fuses - removing each one and examining for the presence of an 'S' shaped fuse element between the blades or using a multimeter to measure for 12 volts on the two tiny metal probe points on top of each fuse near each blade. The negative probe is placed in any bare metal of the chassis and the red probe touches each tiny probe spot on the fuse. If done correctly, you should see battery voltage (12.3v-12.5v) on both probe points. If one probe point doesn't display 12v, that fuse may be blown and removal is needed to see if the element is missing. Practice on the engine fuse panel, on any fuse to become comfortable as this will be repeated on every fuse without having to pull each one. 12v should be seen on both probe points.

[joshjani]

Wow thanks for so much good info.

There is no evidence of aftermarket electronics- the radio is the factory CD player, and there's no premium sound...as far as I can see, speakers are stock as well. That doesn't mean the radio wasn't swapped out and back in at some point, so I can certainly get in there and see if a connector is loose or something.

Other things controlled by the BCM, such as locks and dashlights, seem to be working perfectly. I have no issues with any ABS or airbag warnings, and the car runs perfectly.

I have replaced every 10A fuse in the interior fuse panel, regardless of whether it said interior lights or not- I had read in other posts how fuses can sometimes serve more than one system. I have NOT replaced anything in the under-hood fuse box. I will use your suggestion of testing each fuse with my multimeter.

I removed the driver side panel where the door switch is, and the wire looks to be fine. I removed both the dome light assembly and the map light assembly just to look at the switches and wires to see if there were any frays or burns. I also inspected the one ground I could see in the jack compartment and all was clean and good, all wires I could see were taped and dressed as if new.

It really does seem like something is just disconnected or broken, and you're confirming that I need to dig in behind some panels to see what I can see. I'll at least poke around behind the radio and interior fuse panel, just to see if there's anything obviously amiss.

[fdryer]

The bcm is below the radio.

[joshjani]

Originally Posted by fdryer

The bcm is below the radio.

Yes, so I've read. I still have a question about the liftgate switch, though. How can I check the wires/condition of that switch- I cannot find it. Is it inside the latch?

[fdryer]

I'm not familiar with liftgate switches and their location. If its anything like a remote trunk release, I have a button on the left side of the dash labeled with a trunk symbol. Mine (L300) switches a 12v signal to power a solenoid in the trunk latch to release it. Other trunks release using a cable. Electric trunk release allows using remote key fobs to release trunks without using the ignition key. Cable release may be located on the floor by the door.