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 2007 Hummer H3 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owned a 2007 Hummer H3. The contact stated that while the vehicle was parked, the AC was turned on, and the contact became aware of smoke entering the cabin of the vehicle. The smoke was coming from the front passenger's side underneath the dashboard. The AC was turned off, and the smoke ceased. The contact exited the vehicle and went into the store. The contact exited the store and was informed by a shopper that the vehicle was on fire. The vehicle was unoccupied. The fire was coming from underneath the hood of the vehicle. The Fire Department arrived on the scene and extinguished the fire. The Fire Inspector informed the contact that the fire was a thermal event related to HVAC wiring. In addition, the contact was informed of an unknown recall; however, the VIN was not associated with a recall related to the failure. The vehicle was destroyed. …
Odometer Fraud. The contact purchased a 2007 Hummer H3. The contact discovered that there was a mileage discrepancy. The vehicle was an independent dealer sale. At the time of purchase, the vehicle mileage was 122,791 and at the time of registration, it was discovered that the mileage was 122,799 but additional documents also showed that the mileage was unchanged over a 3-year period.
I keep getting a code that states that my truck runs with a low engine temperature. Plus my truck has had a leak from some where around the lower windshield that is causing electrical problems and soaking wet floors! We had a mechanic look for the leak and try to fix this issue but was unable to find the problem and we were also told by a few dealership that they have seen a lot of H3 hummers with the same problem! Also we are having issues that causes the traction signal to come on regularly and it causes my truck to lock up. It has almost caused us to wreck several times! It's very scary to drive my Hummer! Every time we have any of these problems we are always in motion and it's always on the highway when we are driving at higher speeds. It never seems to happen while driving around town!! This has been continuing going on ever since we purchased this vehicle in August 2014
Our 2007 Hummer H3's air conditioning stopped working in May, 2014. We took it to our mechanic and they found burned/melted wires and components related to the blower relay. They replaced parts and wires to return the A/C to working order. Recently, we received the recall notice related to this hazard, but GM doesn't have a solution yet. Today, the selector on the A/C has stopped working. We have a serious concern that wires and components might be burning again. We have stopped driving the car. How can GM get away with this dangerous hazard and not fix our car? I see so many complaints on this website related to this issue. What other agency of the government can influence the car manufacturer to remedy this potentially-deadly defect?
Tl* the contact owns a 2007 Hummer H3. The contact stated that the vehicle stalled several times without warning. The vehicle was towed to a dealer over seven times for unknown repairs but the failure recurred. The contact also stated that the vehicle overheated several times. The contact also smelled strong fumes as if there were wires that could be burning. The dealer was notified of the failure and was unable to replicate the failure. The contact later received notification of NHTSA campaign number: 15V421000 (visibility). The dealer was unable to supply the part within a reasonable timeframe to repair the vehicle. The manufacturer was notified of the failure. The approximate failure mileage was 117,000.
On 3/13/2020 my wife was driving our 2007 Hummer H3 when the engine compartment and dash area caught on fire. The blower motor connector module had been replaced recently as part of a safety recall. The vehicle was in motion and she had just made a left turn. Although the part had been replaced, I still believe that this recall issue was the cause of said fire. The fire department called it an electrical issue. There was no warning at all. This was traumatic for my wife she had to jump out of the vehicle and had a miscarriage.
Tl* the contact owns a 2007 Hummer H3. While driving at approximately 40 MPH, the contact turned on the air conditioner and heard an abnormal noise and smelled a burning odor. The contact stated that this was a recurring failure. The vehicle was taken to the dealer for diagnostic testing. The technician stated that the sensor on the computer under the dashboard needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 100,000.
Tl* the contact owns a 2007 Hummer H3. While the vehicle was parked, the key became stuck in the ignition and could not be removed. The vehicle was towed to a dealer where it was diagnosed that the ignition cylinder failed and needed to be replaced. The dealer made many attempts to repair the vehicle, but the remedy failed. In addition, various electrical functions failed and a burning odor was noticed. The manufacturer was notified of the failure. The failure mileage was 7,000.
Tl* the contact owned a 2007 Hummer H3. While driving 25 MPH, the contact noticed fire under the glove box. The contact coasted the vehicle over to the side of the road and exited the vehicle. The vehicle caught fire. The fire department extinguished the fire. A police report was not filed. The vehicle was destroyed. The manufacturer was not notified of the failure. The approximate failure mileage was 140,000.
Tl* the contact owns a 2007 Hummer H3. While driving approximately 60 MPH, the contact smelled burning plastic. The vehicle became filled with the odor. The dealer diagnosed that the connector model, blower switch, and HVAC unit melted and needed to be replaced. The manufacturer was notified. The approximate failure mileage was 111,000.
Electrical complaints in other H3 years
Frequently asked questions
How common are electrical problems on the 2007 Hummer H3?
NHTSA has 76 complaints about the electrical system of the 2007 Hummer H3, 32% of the model year's 238 complaints. The component named most often is wiring › interior/under dash (2 mentions).
Is there a recall for 2007 Hummer H3 electrical problems?
No. NHTSA lists no electrical system recall for the 2007 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 2007 Hummer H3 electrical problems start?
Half of the complaints with a recorded mileage happened before about 90,000 miles, and 3% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 14 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.