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Power mirror/vanity and domes

Mambachee

Member
Messages
12
Location
East Texas
Domes do not work unless turned on by the power mirror adjustment knob or raising the vanity light. They do not work on open door or manual switch. Thoughts? Thanks
 

alrock

El Diablo
Staff member
Messages
10,677
Location
Scottsdale
Is that for all doors? Typically when people see similar symptoms it's from a bad door switch which is an easy replacement. But I've never heard of adjusting the power mirror or using the vanity mirrors to turn on the dome lights. That points to more of a ground issues or bad BCM. But the first thing - always the first thing on these H3s when there's electrical issues - is to check your battery cables and terminals to make sure they are tight.
 

Mambachee

Member
Messages
12
Location
East Texas
First thing I did was battery terminals, 12.2 not running. BCM appears to be new, bought the alpha used. Everything else electrical wise works as it should. Thanks alrock
 

Jeepwalker

Well-Known Member
Messages
980
Location
WI
Is that an no or nc switch ?

Pg 168 in the owners manual for Dome Light Override says 'To turn the interior lamps OFF (so they don't come on), press the button in'.

That's for an '07, other years may be different. It sound like all of the lights go through (in some way) the dome light switch assembly.

There's a pr of wires that goes from the driver's side vanity mirror and another set for the dome lights. If I recall the dome light travels from the driver's a-pillar above the driver's head and over through to the dome light. The wires for the vanity mirrors go through the visor shaft and then up and down though a hole punched in the front roof framing right above the visor mounting area and a little further back towards the side of the roof near the a-pillar. It's kind of sharp there the small visor wires need to coil quickly in that tight region and the visor spring is there too, meaning there isn't a lot of room for the wires and could easily pinch right above where the visor screws tighten, or rub the plastic off on that punched hole. It's possible the dome light wires are there too and somehow shorted ..who knows?

I had all that stuff apart on mine and I had to take extra care and route the visor light wires a couple times to take care they wouldn't pinch. But that doesn't explain the mirror adj situation. And maybe there are compound problems (frayed door wires). Perhaps unhook the mirror sw. I'm trying to remember if the mirror adjustment goes through the driver's door sw, but I don't think it does. So, there are a couple things to look at.
 
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Jeepwalker

Well-Known Member
Messages
980
Location
WI
To drop the headliner in that region, you would:

1) pull off the ABS plug on the a-pillar vertical plastic trim. There's a screw behind that plug (no abs airbag there). Then use your hands to pull off the plastic piece (there are metal clips holding it on).
2) remove drivers side inner door gasket around the headliner area. You don't have to remove the entire gasket, just the top portion. Let the rest hang.
3) Remove visor mounting screws and inspect the visor vanity mirror wires. If you can get access to the plug, unplug the light wire ..or just let the visor hang carefully.
4) At that point you should be able to carefully pull down the edge of the headliner in the front driver's corner a couple inches and look in there and inspect the wires that go to the dome light possibly with a flashlight. I 'believe' they travel from the drivers side, rather than the passenger's side. You should see once you get access. If not try the same on the pass side and see if you find the dome light wires.

Shouldn't take more than 10 minutes to drop the headliner corner as i've outlined ..for a quick look.
 
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Jeepwalker

Well-Known Member
Messages
980
Location
WI
The PCM "could" have been replaced by the previous owner trying to resolve the same interior lighting issue, who knows? The best I can advise is try to cross off all normal wiring issues first: Door wires frayed, visor wire shorts, lighting switch assembly, fuse block corrosion, previous owner wiring snafu's, body grounds (not just battery grounds) ..etc. Maybe see if you can get your hands on a wiring diagram.

There are several grounds on the body on the H3. For instance, right under both seats beneath the carpeting there are connectors that act as grounds bolted to the floor. On mine, the wire where it entered the connector ..on the driver's side was mysteriously badly corroded. I cleaned and attached a new connector. So, there are several body grounds from the harness. As many as you can prove 'good' the better, including from the battery.
 
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chaynes

Member
Messages
16
Location
SEMI
Hoping you can figure this out because I have similar issues.

Foot well lights come on fine, but domes do not. I checked the bulbs and they are fine, no voltage going to the dome light terminals under any conditions. PO had switched out for LED bulbs at some point....

I suspect it’s an issue in the wiring / grounds, or a problem with the dome light defeat switch, or the BCM. Looks like the domes are driven off a different circuit from the footwell lights at the BCM.

Wiring diagrams may be found at schwarttzy.com in the H3 guide:

https://schwarttzy.com/wp-content/uploads/2013/01/Hummer-H3-Lighting-1-4-1.pdf

With those guides I’ve been able to troubleshoot quite a few things, but this still is ongoing.




Sent from my iPhone using Tapatalk
 

Jeepwalker

Well-Known Member
Messages
980
Location
WI
I wonder if the LEDs would cause some sort of BCM circuit burn-out?

I was at Advance Auto Parts about a month ago for some parts, the manager was trying to talk me into putting $15 LEDs in my dome lights. I'm like '..um...I don't THINK so."
 

Mambachee

Member
Messages
12
Location
East Texas
I wonder if the LEDs would cause some sort of BCM circuit burn-out?

I was at Advance Auto Parts about a month ago for some parts, the manager was trying to talk me into putting $15 LEDs in my dome lights. I'm like '..um...I don't THINK so."

thanks for all the info Jeepwalker, I’m going to start with the grounds under the seats. It had a new carpet kit from GM put in before I bought it. Then if that’s not it go from there.
 

Jeepwalker

Well-Known Member
Messages
980
Location
WI
If you remove the driver's side sill plate (just gently pull 'up' with your hands ...wiggling as you do to release the clips) ...if you remove the sill plate you may be able to lift the carpet up enough to see the ground connector w/o pulling the seats. Even so, the seats only have 4 easy to remove bolts and a couple harness clips and can be removed in 10 minutes (although they're kind of heavy). You should be able to lift the carpet up to fix if they're corroded. Same with the pass side. The ground fastener is appx 5-6" in from the sill plate as I recall.

I'm sure there are more than a few grounds under the dash and footwell areas (possibly) too. All the plastic pieces on the inside come off really easily with metal clips ..some panels may have a screw here and there, but easy to get off and put back on. I've had mine off a bunch of times to resolve issues. After many years working on cars and swearing at how interiors were put together I really like how GM *finally* produced interior panels which could be removed and reinstalled nearly infinitely w/o damage. :)
 
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