H2 Rear Passenger Door Locks

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#1
Hi All, the folks down at AutoZone suggested I use BAT Auto for my DIY needs so thought I'd give it a shot :)

I have a 2008 Hummer H2 and have an odd issue with the rear passenger doors not unlocking. The odd part is that they will lock when I put it in drive, so the actuator is working, I suppose. But when I hit the unlock on the remote or on the driver doors, only the front two doors respond appropriately. The rear doors will never unlock, no matter how many times I use the remote or hit the unlock buttons.

But when they are unlocked and I take off, they will lock. I get that the auto lock set under my preferences as this has been set since I bought the hummer.

So in short, remote and lock button will lock all four doors. The remote and unlock button will only unlock the driver doors. With all four doors unlocked, when I put it drive, all doors lock as expected.

Also, I'm not sure if there is anything tied to this or if it's a coincidence in timing, my side mirrors aren't responding to the buttons to adjust and when I put it in reverse, it no longer lowers the angle to assist parking. This may be a fuse. If you think so, could you give some direction?

Thank You in advance for your assistance,
Rick
 
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#2
both lead to door 'modules'... may need reconfiguring or replacement... access to GM data and interface...dosn't look like a DIYer.
Your friendly authorized GM Hummer dealer will gladly assist - there are TSB's for both issues -

PS - first are there any codes or modifications ie added alarm or remote?
 
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#3
Have you replacedyour 12 volt car battery lately? The one that is under the hood and not refering to your fob. When my battery goes dead or is replaced , I have to go into the program on the dash setup on the accessories and reprogram my mirrors to go down when backing up. You can have it where it will do that or not in the program. I don't know if there is an option in that program that only controls the drivers door or not. Just another thought.
 
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#4
I read it as he has set his preferances AND still not working?
"I get that the auto lock set under my preferences ...." leaving me thinking he is aware of what I would call step 1... anyway here is some info
page 2-11 to start

http://www.hummer.com/content/dam/hummer/northamerica/usa/nscwebsite/en/Home/Owners/Owner_Resources/Manuals/en/us/2008/h2/2008-hummer-h2-owners-manual.pdf
 
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#5
That is why I asked him if the battery run down or has it been changed lately. When mine runs down the mirrors has to be reset. Maybe the locks have too also if the battery runs down or is changed. Just a thought. It says in your reference address that the unlock part of the door can be programmed to open or not any door.

I don't have a schematic on the 2008 , but I would not think they would have a separate fuse for automatic lock and automatic unlock, but maybe they do.
 
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#6
That new Cruze I purchased has all this crap, hidden inside of the radio, has a tiny button that is hardly noticeable under the power window switches. A push button switch if activated prevents the rear doors from unlocking, some kind of alternate solenoid that does not depend on battery voltage.

Its all clearly written on page 300 and something in the owners manual and easy enough to bump when you get into the vehicle. In trying to comprehend the various options, some Chinese or Indian guy must have wrote that manual, so I had to play with it.

And had to worn my wife not to play with that Config switch right next to the aux switch on the radio for selecting CD's, USB, Auxillary, or the Radio, could really mess it up. She still absently hits what she thinks is the cruise button at the end of the directional single knob where GM had that for the last 45 years. And hopefully just resets the fuel used, but one time reset the oil remaining life or one of the two trip odometers.

With that child safety switch on, you can actually lock yourself up in the back seat, but with a strong stretch over those tall head restrains, can hit that button so you can get out.

They so they for our safety.
 

Gus

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#7
Never worked on a Hummer, the vehicle or whatever, .......

My guess is since neither door lock switch or remote switch unlocks the rears, it could be a "personalization" problem, or the circuitry somehow involves a separate unlock relay, or it could be a BCM problem.....
 
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#8
Could add to the confusion, every door lock motor I have seen was a permanent magnet motor with a rack and pinion. Either locks or unlocks by applying voltage and reversing the polarity. So if it works in one direction should work in the other. What's different are the point contact relays for locking or unlocking, things really have a high surge current so could be a dirty contact.

With this Cruze, counted 52 push button switches within the driver's reach, that is history now, going to a touch screen, much cheaper. They fire commands to the BCM that in turn fires relays. Owners manual only shows two locations for these relays, most are in a fuse box under the hood, other are in the fuse panel under the dash. But not a single relay listed for the doors locks.

Guys were asking about adding electrically heated seats, another push button inside of the blower motor and temperature control knobs. All I could say to help them, I heard relay noises somewhere behind the radio. But can't do that with the door locks, they make way too much noise to tell where those relays are located. Would have to get a shop manual to learn that.

Ha, could get a Haynes manual, but if anything more complicated than replacing a tire valve cap, tell you to take it to a dealer.
 
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#10
kev2 said:
both lead to door 'modules'... may need reconfiguring or replacement... access to GM data and interface...dosn't look like a DIYer.
Your friendly authorized GM Hummer dealer will gladly assist - there are TSB's for both issues -

PS - first are there any codes or modifications ie added alarm or remote?
Hi All, my apologies on the delayed responses to all the helpful posts as I've been out of town. Kev2, I have indeed had modifications by way of retractable running boards, 15" lift (probably not relevant), and HID headlamps. Everything else is still functional and working fine for three years.
 
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#11
The old man said:
Have you replacedyour 12 volt car battery lately? The one that is under the hood and not refering to your fob. When my battery goes dead or is replaced , I have to go into the program on the dash setup on the accessories and reprogram my mirrors to go down when backing up. You can have it where it will do that or not in the program. I don't know if there is an option in that program that only controls the drivers door or not. Just another thought.
Thanks The Old Man and yes I have replaced my battery but as suggested later in the threads, I have the correct settings under the programing but there is no movement at all when trying to set the mirrors, regardless of the assisted reverse.
 
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#12
If I have the story right the remote will lock all doors but only unlock driver door. Try pushing the unlock button twice. The first should unlock driver's door the second should unlock the rest. Now from what I read from inside you can lock but not unlock rear doors. Sound like a child safety doorlock issue. Not sure if you have an switch or an actual lever on the door you have to move to unlock position. HTH Greasemonkey :)
 

kev2

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#13
the child safty door locks my colleague mentions - the info is in the link* I provided
Off the top of my head they are MANUAL levers on the door latchs.

I asked about modifications 2 reasons- 1)the TSB mentions mods AND any other codes.
2) experiance- problematic esp with intergrated modules...


*post # 3 april 28