Which parts fail
Components named in complaints (battery, alternator, wiring, ignition, instrument cluster, infotainment).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2008 Hummer H3 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2008 Hummer H3. The contact stated that upon shifting into drive (D) or reverse (R) the doors of the vehicle would unlock automatically. There was no warning light illuminated. The contact also stated that upon pressing the power master door lock switch to lock the vehicle, all four doors were unlocked. Additionally, the contact stated after refilling the gas tank at the gas station, the vehicle failed to restart and made an abnormal clicking sound. The contact stated that upon inspecting the hood of the vehicle, he saw flames on the positive side of the battery and the flames extended to the oil stick. The contact was able to extinguish the fire by taping it with a towel. The vehicle failed to start and remained at the gas station. The dealer and the manufacturer were not notified of the failure. The vehicle was not diagnosed or repaired. …
The contact owns a 2008 Hummer H3. The contact stated that the vehicle failed to start. The anti-theft system warning light illuminated. The contact waited 10 minutes for the vehicle to reset, per the vehicle Owner's Manual instruction. The contact was able to drive the vehicle. The contact stated that the failure reoccurred increasingly several times per day. Additionally, the vehicle had taken 45 to 90 minutes to reset and restart. The vehicle was towed to an independent mechanic on two occasions; however, the mechanic was unable to duplicate the failure as the vehicle would restart as needed while at the dealer. The dealer and the manufacturer were not notified of the failure. The vehicle was not diagnosed nor repaired. The failure mileage was approximately 101,421.
The contact owns a 2008 Hummer H3. The contact stated that the vehicle intermittently failed to start up without warning. The contact stated that after waiting ten minutes the vehicle started. The contact stated that recently the failure had become more frequent. The contact had taken the vehicle to a dealer however, the mechanic was unable to determine the cause of the failure. The manufacturer was not notified of the failure. The vehicle was not repaired. The failure mileage was approximately 1,000.
The last dealership I went to they advised to come th the dealership but when I got there nobody wasn't trying to work there instead the said that it was going to be hard to work on it cause nobody work on those cars anymore and then they said they were going to order the part but never call me back for it. Call them but gave me the runaround basically.
The pass lock in this vehicle is faulty. On numerous occasions, it has left me unable to start the vehicle, but if you wait 10 minutes each time, it will start again, but it happens all the time. I've seen numerous complaints online and GM needs to do something about it.
Tl* the contact owns a 2008 Hummer H3. The contact stated that the air conditioning and heating system would independently shut off. The vehicle was taken to the dealer where it was diagnosed that the blower motor and the wire harness needed to be replaced. The vehicle was repaired however, months later, the failure recurred. The vehicle was taken back to the dealer where it was informed that the ac could not be charged and the radiator the ac alternator and the battery needed to be repaired. The vehicle was repaired however a month later then the vehicle began to over heat and fail to start. The vehicle was taken back to the dealer who, stated the ignition switch needed to be replaced. In addition, the contact stated that there was a burning odor emitting from the ac ventilation system. …
Tl* the contact owns a 2008 Hummer H3. While driving approximately 50 MPH with the air conditioning unit activated, there was a burning odor inside the vehicle without warning. The air conditioner failed. The vehicle was taken to the dealer where it was diagnosed that the lower resistor and wiring harness failed, melted together, and needed to be replaced. The vehicle was repaired. The contact received notification of NHTSA campaign number: 15V421000 (visibility), however, the part to do the repair was unavailable. The contact stated that the manufacturer exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure. The approximate failure mileage was 82,926. VIN tool confirms parts not available.
It started one morning I went to start my vehicle and it wouldn't start I was getting a (no crank no start).I tested the battery that had been replaced only months before and the battery was fine, I then proceeded to check my ignition and starter fuses and relays all were replaced. I noticed I had a dash light on that was a car symbol not ever dealing with it I talked to a garage and was told it was the anti theft pass lock system and that I could check by letting the key on for 10 mins then when the light goes out start it worked as they said. They suggested I replace the lock assemble which included the lock housing,key cylinder,and pass lock module.I got the parts from my local dealer and had them replaced and re learned car worked fine no light any more for about 4 months. …
It seems that the H3, and quite a few other GM cars of this era, has a fuel cutoff switch enabled by a security system which reads the car's key. However, it also has a huge history of failing to operate even when the proper key is used by the car's owner. This represents a dangerous flaw in the design of these cars, not in the sense that it careen off the road without warning or the like, but that it's already stranded my wife multiple times in dangerous circumstances. The fix is currently to replace, at a cost of $300 plus, the ignition switch with exactly the same part that's failed, which is to say that it's more than likely to fail again, as nothing has been done to re-engineer the failed system. …
I own a 2008 Hummer H3 and for the past 4 1/2 years I have been dealing with issues related to engine not starting when you first get in. If you wait exactly 10 minutes, it starts just fine. I have had dealerships and repair shops look at the vehicle and no one seems to know exactly what is causing this intermitant problem. The company that installed my alarm system thought it could be the ignition and/or the passlock. Apparently, the passlock is what thinks your car is being stolen and shuts it down for 10 minutes. However, they are each $600 and no guarantee that either is the problem and the car is out of warranty. After reading some Hummer forum this appears to be a global problem with all hummers from 2006 to 2010 and GM refuses to admit they have a serious problem and will not submit a recall for the faulty ignition switch.
Electrical complaints in other H3 years
Frequently asked questions
How common are electrical problems on the 2008 Hummer H3?
NHTSA has 34 complaints about the electrical system of the 2008 Hummer H3, 30% of the model year's 113 complaints. The component named most often is horn (1 mentions).
Is there a recall for 2008 Hummer H3 electrical problems?
No. NHTSA lists no electrical system recall for the 2008 Hummer H3, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2008 Hummer H3 electrical problems start?
Half of the complaints with a recorded mileage happened before about 80,000 miles, and 10% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 4 fires and 0 injuries to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.