2006 Hummer H3 Problems

What owners report

Owners of the 2006 Hummer H3 most often describe two recurring patterns: a no-start condition where the engine cranks but the vehicle will not fire for about ten minutes, and a burned blower-motor resistor behind the glove box that can produce smoke or a burning smell. Reports also cover premature engine misfires and valve or head-gasket work, rear leaf springs breaking, and sunroof drains backing up and soaking the interior. Mileage on these complaints is wide, from near-new vehicles to well past 150,000 miles, so many issues appear to be slow-developing rather than sudden.

1. 1
   Engine

   Engine misfire, valve and head gasket problems

   • 58 complaints (16%)
   • median 72,594 mi at 6.8 yrs old (50 state mileage)
   • owner-quoted repair $3,591 (median of 10 quotes)
   • filed 2006–2025

   Owners report rough or erratic idle, hesitation and loss of power, and check-engine codes for misfires, sometimes traced to a cylinder with low compression and valve seat or valve problems. Some complaints describe head gasket replacement recommendations, piston-related repairs, or repeated misfire codes that returned after coils, plugs or emissions parts were replaced. Dealers in some cases could not find a fault code or declined assistance. Typically reported between about 45,000 and 130,000 miles, often noticed during acceleration or while warming up.

   5 related service bulletins

   What to check: Ask for a compression or leak-down test and any history of misfire codes, and check the oil and coolant for signs of consumption or mixing.

   2 excerpts from owner complaints in NHTSA records

   “I recently purchased a 2006 H3. From the day I bought the car I have noticed a weird idle when the vehicle is warming up. Until recently I thought it was the way the vehicle ran normally. I decided to have the vehicle inspected by a mechanic. After being inspected the mechanic noticed the vehicle's valves were not seeded right from the factory, which has caused the misfire, which causes the weird idle. I now am in the process of contacting Hummer to see if there is a solution to the problem. …”

   NHTSA complaint #10264863, filed 2009-04, 61,870 miles

   “I have a 2006 Hummer H3 with app. 79,000 miles on it.. I was driving to work on the highway and halfway there, I started to get a really bad vibration and loud humming noise coming from the driveline. It starts at about 40 MPH and comes and goes every few seconds. Its worse when I hit the gas pedal.. The universal joints have already been replaced due to cracked universal joints for some odd reason.. The top end of the engine had just been rebuilt 2 weeks ago as well due to sticking exhaust valves. …”

   NHTSA complaint #10369837, filed 2010-12, 79,021 miles
2. 2
   Electrical system

   Intermittent no-start (Passlock/ignition security waiting

   • 38 complaints (11%)
   • median 82,500 mi at 10.5 yrs old (30 state mileage)
   • filed 2006–2026

   Owners describe the engine cranking normally but refusing to start, sometimes with a security indicator lit or a message on the dash, then starting fine after roughly ten minutes of waiting. Several say the condition appears more often in the morning or after the vehicle sits unused, and that dealers and independent shops replaced batteries and other parts without resolving it. Some complaints note the key becoming stuck in the ignition or the instrument panel lighting up with the fault. Reported across a wide mileage range, from around 65,000 to 200,000 miles, and often described as intermittent over months or years.

   What to check: Start the truck from cold and again after it has sat; ask whether the ignition switch or Passlock-related parts have been replaced, and whether the no-start waiting period has occurred before.

   2 excerpts from owner complaints in NHTSA records

   “I have a 2006 Hummer H3, every few weeks or so the motor will turn over but will not start. I let it sit for a while and then it will start. I have taken it to both the dealer and another mechanic but neither can find anything wrong with it. About 6 months ago, I got a new battery thinking that would solve the issue but it has not.”

   NHTSA complaint #10396621, filed 2011-04, 79,000 miles

   “My 2006 H3 has sporadic issues with starting for a few years now. When I try to start it, it will crank fine but will not start. If I wait approximately 10 minutes & try again, it starts with no problems. During this issue, everything else works in the vehicle (radio, lights, etc..). I've had it checked by several mechanics & replaced lots of parts but didn't help this issue at all. I have read many complaints reference this same exact issue online & through NHTSA but nobody has had any positive responses. …”

   NHTSA complaint #11183206, filed 2019-02, 95,000 miles
3. 3
   Visibility (wipers, defrost, mirrors)

   Blower motor resistor and wiring burns out

   • 53 complaints (15%)
   • median 83,500 mi at 7.0 yrs old (44 state mileage)
   • 19 mention a crash, fire or injury
   • filed 2009–2025

   Complaints describe the HVAC blower stopping entirely, often with a burning plastic smell or smoke behind the glove box, and inspection showing the resistor and its harness connector melted or charred. Some owners report the fan working again only after replacing the resistor, harness and blower motor, and one describes a fire that spread from under the dash. Others received notice of a recall for the blower motor connector but were told the part was not available. Mostly reported between roughly 62,000 and 120,000 miles, with no clear seasonal pattern in the sample.

   Recall 15V4210001 related service bulletin

   What to check: Run the blower on every speed setting and check behind the glove box for a melted resistor connector or a burnt smell; ask whether recall 15V421000 was performed.

   2 excerpts from owner complaints in NHTSA records

   “The blower on my 2006 Hummer H3 stopped working while driving down the highway and we smelled a burnt plastic smell when the blower stopped. The smell eventually went away, but the blower never worked again. I found that this is a huge issue for not just Hummer owners, but other GM vehicle owners. The resistor and plastic clip were melted together and when disconnected, fire damage was evident. …”

   NHTSA complaint #10436461, filed 2011-11, 65,000 miles

   “Smelled burning smell intermittently, then one day blower just quit blowing any type air, did research found the problem to be the blower motor resistor, resistor and harness had melted so replaced it and worked fine but never really worked on the number 1 setting again. Has now happened again january 29, 2014, burning smell and just quit working again. Thankfully not expecting 0 degree temps again before I can get the parts and get it fixed again. Ordered the blower motor, wiring harness and resistor this time. …”

   NHTSA complaint #10562517, filed 2014-02, 62,500 miles
4. 4
   Suspension

   Rear leaf spring fracture or detachment

   • 18 complaints (5%)
   • median 108,260 mi at 11.8 yrs old (14 state mileage)
   • filed 2014–2026

   Complaints describe a loud pop or abnormal noise from the rear while driving or turning, followed by the discovery that a rear leaf spring has cracked, shifted or separated from its mounting. Owners report the vehicle veering or the wheels shifting position, and dealers confirming the spring needs replacement; some were told by the manufacturer that the vehicle was not covered by a recall. Mostly reported between about 104,000 and 140,000 miles, while driving or turning at ordinary speeds.

   What to check: Inspect both rear leaf springs and their mounts for cracks, rust or shifting, and listen for a pop or clunk from the rear on a test drive over uneven ground.

   2 excerpts from owner complaints in NHTSA records

   “Was making a right turn,heard a loud pop was able to get home.upon inspection the rear driver side leaf spring fractured.after researching this must be an ongoing issue,but no recall.”

   NHTSA complaint #11377123, filed 2020-11, 135,000 miles

   “The contact owns a 2006 Hummer H3. The contact stated while driving 10 MPH, the contact heard a pop from the rear passenger's side of the vehicle. Upon investigation, the contact associated the failure with the leaf springs. The vehicle was awaiting a tow. The vehicle was not diagnosed nor repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 111,000.”

   NHTSA complaint #11394868, filed 2021-02, 111,000 miles
5. 5
   Body and structure

   Sunroof drain tubes clog and water enters cabin

   • 20 complaints (6%)
   • median 87,178 mi at 6.6 yrs old (18 state mileage)
   • filed 2009–2024

   Owners describe water entering the cabin during rain, sometimes in sheets from the sunroof area, soaking the floorboards and carpet and producing a mildew smell. Complaints say the sunroof drain lines are too small or clog with debris and back up even when the roof is never opened, and that dealers recommended retrofitting larger lines at the owner's expense. Some mention concern about water reaching electrical components. Reported from roughly 73,000 to 153,000 miles, during rain whether parked or moving.

   What to check: Pour water into the sunroof tray and confirm it drains under the vehicle, and check the headliner, carpets and footwells for stains, dampness or a mildew smell.

   2 excerpts from owner complaints in NHTSA records

   “I have owned this truck since 2009, and it seems to be a common problem with the sunroof drain tubes clogging. When my vehicle was under warranty, and was going in for it's scheduled pmis I would have them blow the drain tubes out with air, but the clogging is now becoming more frequent, and the water if not removed can cause havoc with the cloth, electrical & flooring. Last week I had a mildew smell because of all the rain we have had, and the water built up in the sunroof drain area. …”

   NHTSA complaint #10500803, filed 2013-02, 76,741 miles

   “H3 |drainage problem I paid to have it fixed a year ago and it is blocked up again. My wife had the same problem with her H3. I have had cars and trucks and have never had this problem before with there sun roofs. I know I'm not the only one out here that's had the same problem . When at the dealership one of the shop mechanics said the design was a poor construction and design.the company should be doing something about there design and fix it or have a program to keep them from flooding . It could lead to electrical problems . …”

   NHTSA complaint #10413220, filed 2011-07, 93,356 miles

Buying note. These are older vehicles with a long complaint history, so a pre-purchase inspection covering the ignition/no-start behavior, blower circuit, rear springs and sunroof drains is worthwhile. Service records showing recent work on those areas matter more than mileage alone.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.