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Jared D
Jared D, ASE Certified Technician
Category: GM
Satisfied Customers: 1693
Experience:  Shop Supervisor at County Fleet
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I own a 2007 hummer h2, I have a service 4wd message on the

Customer Question

i own a 2007 hummer h2, I have a service 4wd message on the dash and no lights light up on the transfer case buttons.
JA: Have you checked the fuses? The dashboard bulbs?
Customer: is there a fuse just for those buttons? the rest of the dash seems to be working fine
JA: What is the make/model of your car?
Customer: 2007 Hummer H@
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: 2
JA: Anything else you want the mechanic to know before I connect you?
Customer: I need to know if I can drive it with none of those lights on
Submitted: 6 months ago.
Category: GM
Customer: replied 6 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Jared D replied 6 months ago.

Hi,

This is really common on these trucks. The most likely cause is a failed transfer case control module, but it could also be something as simple as a reprogram is needed. GM released a bulletin calling for a re-flash of the computer programming that controls the transfercase on this model in 2009. It's possible that the re-program was never done and now that some parts have worn a little it's starting to act up.

Do you plan to do any diagnosis/repairs yourself?

Customer: replied 6 months ago.
No, most likely I would take the truck to s repair shop.
Can I still drive the truck in this condition?
Expert:  Jared D replied 6 months ago.

Absolutely. The only thing to be concerned about is that the 4wd won't work until you have the problem fixed. The truck should run normally in 2wd. We see these trucks with this problem all of the time.

Customer: replied 6 months ago.
it is safe to drive, even though, no lights light up on the transfer case switches or neutral?
Expert:  Jared D replied 6 months ago.

Yes, the transfer case is just stuck in 2 high and will not be able to shift into any other gear unless it is shifted manually or with a compatible scan tool. Shifting it manually is nearly impossible without disassembling the transfer case encoder motor on this truck though.

Expert:  Jared D replied 6 months ago.

No lights on the transfer case switch tells me that the problem is most likely a bad transfer case control module rather than a re-program issue.

Customer: replied 6 months ago.
Last question, since hummer was closed, who would you suggest for servicing this trucks?
Customer: replied 6 months ago.
I should not freak out about the Service 4WD on the dash either?
Expert:  Jared D replied 6 months ago.

A Chevy or GMC dealer should be able to take care of it. This truck uses all of the same parts as the silverado, sierra, yukon, tahoe, suburban so everything should be available and their computer scan tools will hook right up.

No, the service 4wd message is just alerting you that there is a problem. It's safe to drive, the 4wd just won't work.

Expert:  Jared D replied 6 months ago.

This is the TSB I was referring to from GM:

Expert:  Jared D replied 6 months ago.

That could be the issue, but it's most likely going to need a transfer case control module.

Customer: replied 6 months ago.
Thx, have a great evening
Expert:  Jared D replied 6 months ago.

Please let me know if you need additional info.

Also, please don't forget to rate.

Expert:  Jared D replied 6 months ago.

Please don't forget to rate- that's how Just Answer compensates me for my time.