IllustrationSPEEDOMETER STOPPED WORKING WHILE DRIVING ON HIGHWAY. *TR
2004 Chevrolet Trailblazer
Owner reports · Recalls · Investigations
More warning signs than most Trailblazer years
Owner complaints for the 2004 Chevrolet Trailblazer are substantially higher than the model-year median of 87.5.
About this comparison →How this year compares
Owner complaints by model year
Compare all Trailblazer years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
All reported categories
Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
880–25K
16325–50K
27450–75K
17675–100K
137100–150K
61150K+
899 reports with mileage · 182 unknown
NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.
What to inspect
Issues worth paying extra attention to based on owner reports.
- Electrical System. Review the 627 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Exterior Lighting. Review the 101 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
- Fuel System, Gasoline. Review the 93 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
NHTSA owner reports · September 18, 2026 snapshot.
56 crash reports31 fire reports47 injury reports
Electrical System complaints
627 reportsSPEEDOMETER NOT INDICATING CORRECTLY ON 2004 CHEVY TRAILBLAZER. GM WILL NOT COVER REPLACEMENT COST OF INSTRUMENT CLUSTER EVEN THOUGH THEY HAVE RECALLED FULL SIZE PICKUPS AND SUVS FOR SAME PROBLEM. MANY COMPLAINTS FOR SAME PROBLEM REGISTERED ON VARIOUS INTERNET SITES. CANNOT TELL CORRECT SPEED VEHICLE IS TRAVELING, AND NOT CONFID…
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SPEEDOMETER NOT INDICATING CORRECTLY ON 2004 CHEVY TRAILBLAZER. GM WILL NOT COVER REPLACEMENT COST OF INSTRUMENT CLUSTER EVEN THOUGH THEY HAVE RECALLED FULL SIZE PICKUPS AND SUVS FOR SAME PROBLEM. MANY COMPLAINTS FOR SAME PROBLEM REGISTERED ON VARIOUS INTERNET SITES. CANNOT TELL CORRECT SPEED VEHICLE IS TRAVELING, AND NOT CONFIDENT IN OTHER SYSTEM INDICATORS ON INSTRUMENT PANEL. *TR
2004 CHEVROLET TRAILBLAZER INSTRUMENT CLUSTER INTERMITTENTLY WORKS. SOMETIMES ONE THING WORKS, SOMETIMES NONE, SOMETIMES ALL. ABS LIGHT FLASHES ON AND OFF CAUSING WARNING BELL TO RING INTERMITTENTLY. I FELL THAT THIS IS UNSAFE SINCE THE SPEEDOMETER WILL NOT WORK. I HAVE TALKED WITH OTHERS THAT HAVE HAD SIMILAR PROBLEMS. *TR
MY INSTRUMENT PANEL ABS, AIRBAG, BATTERY, AND BRAKE LIGHTS ALL CAME ON WITH THE TEMPERATURE, FUEL, BATTER VOLTAGE, AND OIL PRESSURE GAUGES NOT WORKING. AFTER A FEW DAYS MY BATTERY WENT DEAD. REPLACED THE BATTERY THINKING THIS WAS CAUSING THE PROBLEM THEN NONE OF GAUGES WORKED AND ALL THE PANEL LIGHTS WERE OFF. NOTHING WAS HAPPEN…
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MY INSTRUMENT PANEL ABS, AIRBAG, BATTERY, AND BRAKE LIGHTS ALL CAME ON WITH THE TEMPERATURE, FUEL, BATTER VOLTAGE, AND OIL PRESSURE GAUGES NOT WORKING. AFTER A FEW DAYS MY BATTERY WENT DEAD. REPLACED THE BATTERY THINKING THIS WAS CAUSING THE PROBLEM THEN NONE OF GAUGES WORKED AND ALL THE PANEL LIGHTS WERE OFF. NOTHING WAS HAPPENING ON THE INSTRUMENT PANEL. STARTED THE CAR THE NEXT DAY AND HAD ORIGINAL PROBLEM. DEALER CHECKED IT OUT AND RECOMMENDED A NEW INSTRUMENT PANEL CLUSTER MODULE AT ABOUT $475 INSTALLED. VERY BIG SAFETY ISSUE IF YOU CAN'T TELL WHAT'S GOING ON WITH YOUR CAR LIKE GAS LEVEL AND ENGINE TEMPERATURE. *TR
SPEEDOMETER WILL INTERMITTENTLY SHOW SPEED MUCH FASTER THAN ACTUAL SPEED. FOR EXAMPLE, SHOWING 120+ MPH WHEN ONLY GOING 40MPH. *TR
SPEEDOMETER ON MY 2004 CHEVROLET TRAILBLAZER LT IS DISPLAYING ERRATIC READINGS. WHEN THE VEHICLE IS PARKED THE SPEEDOMETER IS SHOWING THE VEHICLE IS MOVING AT 40 MPH. WHEN DRIVING AT SPEEDS APPROXIMATELY 40 MPH THE SPEEDOMETERS SHOWS THE VEHICLE IS MOVING AT 90 MPH. MULTIPLE POSTS REGARDING THIS ISSUE ONLINE. FAULTY INSTRUMENT…
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SPEEDOMETER ON MY 2004 CHEVROLET TRAILBLAZER LT IS DISPLAYING ERRATIC READINGS. WHEN THE VEHICLE IS PARKED THE SPEEDOMETER IS SHOWING THE VEHICLE IS MOVING AT 40 MPH. WHEN DRIVING AT SPEEDS APPROXIMATELY 40 MPH THE SPEEDOMETERS SHOWS THE VEHICLE IS MOVING AT 90 MPH. MULTIPLE POSTS REGARDING THIS ISSUE ONLINE. FAULTY INSTRUMENT CLUSTERS ON THESE VEHICLES. ALSO, BEFORE THE SPEEDOMETER BEGAN SHOWING ERRATIC READINGS TODAY, THE SPEEDOMETER DIDN'T MOVE SMOOTHLY. WHEN ACCELERATING THE SPEEDOMETER MOVED ONE TICK AT A TIME, SIMILAR TO HOW THE SECOND HAND ON A CLOCK MOVES. THE NEXT TIME I GOT IN THE CAR AFTER THIS HAPPENED IS WHEN THE SPEEDOMETER STARTED SHOWING INACCURATE SPEED RATINGS. THIS IS A SAFETY ISSUE SINCE YOU CAN NOT TELL HOW FAST THE VEHICLE IS TRAVELING. MY VEHICLE CURRENTLY HAS 65,000 MILES. I PURCHASED IT 2.5 YEARS AGO WHEN IT HAD 29,000 MILES AT CARMAX. I HAVEN'T HAD THE VEHICLE REPAIRED YET, BUT ALL POSTS I HAVE READ ONLINE INDICATE THAT THE ENTIRE INSTRUMENT PANEL WILL NEED TO BE REPLACED. *TR
ENTIRE INSTRUMENT PANEL NOT WORKING IN MY 2004 CHEVROLET TRAILBLAZER. FIRST INCIDENT 10/16/2009, CORRECTED ITSELF WITHIN 10 MINS. STOPPED WORKING AGAIN 10/25/2009, NO SELF CORRECTION THIS TIME, NOT WORKING AT ALL. CALLING CHEVY DEALERSHIP TOMORROW. *TR
LOW BEAM HEADLIGHT CONNECTION SHORTS OUT AND BURNS, AND HEATER AND A/C CONTROLS DON'T WORK ANYMORE WHEN YOU TRY TO TURN ON HEAT OR A/C KILLS ENGINE. I HAVE ALREADY REPLACED THE LIFTGATE MODULE, THAT FIXED THE PROBLEM OF NOT BEING ABLE TO LOCK THE VEHICLE AND SOMETIMES STARTING IT. THIS ALL STARTED AT ABOUT 92,000 MILES. ESTIMATE…
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LOW BEAM HEADLIGHT CONNECTION SHORTS OUT AND BURNS, AND HEATER AND A/C CONTROLS DON'T WORK ANYMORE WHEN YOU TRY TO TURN ON HEAT OR A/C KILLS ENGINE. I HAVE ALREADY REPLACED THE LIFTGATE MODULE, THAT FIXED THE PROBLEM OF NOT BEING ABLE TO LOCK THE VEHICLE AND SOMETIMES STARTING IT. THIS ALL STARTED AT ABOUT 92,000 MILES. ESTIMATED REPAIR COST FOR HEAT AND A/C AROUND $600.00. *TR
I PURCHASED A 2004 CHEVY TRAILBLAZER LT V6, AND MY GAUGES FLUCTUATE SO MUCH THAT I DO NOT KNOW HOW FAST I'M GOING, IF I REALLY NEED GAS, IF MY ENGINE IS RUNNING HOT OR NOT...I'M AFRAID TO DRIVE THE VEHICLE. I STARTED TO RENT CARS WHEN I NEEDED TO TRAVEL OUT OF TOWN, BECAUSE I WAS CONCERN ABOUT MAKING IT TO MY DESTINATION AS WEL…
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I PURCHASED A 2004 CHEVY TRAILBLAZER LT V6, AND MY GAUGES FLUCTUATE SO MUCH THAT I DO NOT KNOW HOW FAST I'M GOING, IF I REALLY NEED GAS, IF MY ENGINE IS RUNNING HOT OR NOT...I'M AFRAID TO DRIVE THE VEHICLE. I STARTED TO RENT CARS WHEN I NEEDED TO TRAVEL OUT OF TOWN, BECAUSE I WAS CONCERN ABOUT MAKING IT TO MY DESTINATION AS WELL AS COMING BACK HOME SAFELY. I HAVE BEEN SO UPSET AND TRYING TO FIGURE OUT WHAT TO DO. I START LOOKING FOR A COMPANY/GROUP TO HEAR MY CRY...AS I SURFED THE INTERNET, I FOUND SEVERAL INTERESTING STORIES SIMILAR TO MY COMPLAINT AND NOTHING HAS BEEN DONE TO CORRECT THE PROBLEM. I WILL NOT BE PURCHASING ANOTHER GM PRODUCT ANYMORE, BECAUSE AS A CONSUMER, I DESERVE TO HAVE A PROBLEM FIXED/SOLVED IF I PURCHASE A PRODUCT OR SERVICE FROM AN ORGANIZATION. I HOPE AND PRAY THAT NO ONE GETS HURT OR KILLED AS A RESULT OF THIS PROBLEM WITH THE CHEVY TRAILBLAZER VEHICLES. I WOULD LOVE TO GET MY VEHICLE FIX WITHOUT HAVING TO PAY $500-800, BECAUSE FRANKLY I DO NOT HAVE THAT KIND OF MONEY TO SPEND. THANKS FOR ALL YOUR HELP!! *TR
MY DAUGHTER DRIVES A 2004 CHEVY TRAILBLAZER. SHE WAS DRIVING HOME FROM COLLEGE THE OTHER DAY WHEN THE ENGINE SUDDENLY CUT OFF ON THE HIGHWAY. SHE STILL HAD USE OF THE GAS PEDAL AND STEERING BUT ALL OTHER FUNCTIONS STOPPED. FORTUNATELY, SHE WAS IN HEAVY TRAFFIC, GOING SLOWLY AND WAS ABLE TO ROLL TO A STOP ON THE SHOULDER. AFTER …
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MY DAUGHTER DRIVES A 2004 CHEVY TRAILBLAZER. SHE WAS DRIVING HOME FROM COLLEGE THE OTHER DAY WHEN THE ENGINE SUDDENLY CUT OFF ON THE HIGHWAY. SHE STILL HAD USE OF THE GAS PEDAL AND STEERING BUT ALL OTHER FUNCTIONS STOPPED. FORTUNATELY, SHE WAS IN HEAVY TRAFFIC, GOING SLOWLY AND WAS ABLE TO ROLL TO A STOP ON THE SHOULDER. AFTER ABOUT 5 MINUTES, SHE WAS ABLE TO RESTART THE VEHICLE AND DROVE THE REST OF THE WAY HOME WITHOUT INCIDENT. SINCE MY HUSBAND AND I DECIDED THAT IT WAS TOO DANGEROUS FOR HER TO DRIVE BACK TO SCHOOL, WE TOOK THE CAR IN FOR SERVICE. I MIGHT ADD THAT THERE WAS A RECALL OF THIS VEHICLE IN 2007 (?) THAT INVOLVED "CORROSION IN THE FUEL TANK MODULAR RESERVOIR ASSEMBLY." THIS RECALL ITEM WAS REPLACED BY CHEVROLET WHEN WE TOOK IT IN FOR SERVICE BUT THE TECHNICIAN SAID IT PROBABLY HAD NOTHING TO DO WITH THE INCIDENT ON 10-9. SO, AFTER "EXTENSIVE ADDITIONAL DIAGNOSTICS" AND A FEW TEST DRIVES, CHEVY TECHNICIANS SAID THEY COULD FIND NOTHING FURTHER WRONG WITH THE VEHICLE AND WERE UNABLE TO DUPLICATE THE INCIDENT. ADDITIONAL INFORMATION: WE BOUGHT THE CAR FROM CARMAX APPROXIMATELY 1.5 YEARS AGO. I SHOULD ALSO MENTION THAT THE SAME THING HAS HAPPENED AT LEAST TWO TIMES PRIOR TO THE OCTOBER 9, 2009 INCIDENT, BUT AT THE TIME, IT JUST SEEMED LIKE A GLITCH. IN THE PAST FEW DAYS, I HAVE BEEN ON THE INTERNET READING ABOUT MANY SIMILAR INCIDENTS (AMONG OTHER TROUBLING FLAWS WITH THIS CAR) WITH THE 2004 CHEVY TRAILBLAZER. IN SOME CASES, THE VEHICLES WERE GOING AT HIGH SPEED WHEN THEY SHUT DOWN. HERE ARE THE LINKS: HTTP://WWW.ABOUTAUTOMOBILE.COM/COMPLAINT/2004/CHEVROLET/TRAILBLAZER HTTP://WWW.CARCOMPLAINTS.COM/CHEVROLET/TRAILBLAZER/2004/ELECTRICAL/GAUGES_FLUCTUATE.SHTML I AM TERRIFIED THAT THIS WILL HAPPEN AGAIN AND THAT THE OUTCOME WILL NOT BE GOOD. COULD YOU PLEASE TELL ME WHY HAS THERE NOT BEEN A RECALL ON THIS VEHICLE FOR WHAT APPEARS TO BE AN EXTREMELY DANGEROUS CONDITION. *TR
Official recalls
205V198000 · Exterior Lighting:turn Signal
May 5, 2005
ON CERTAIN TRUCKS AND SPORT UTILITY VEHICLES, THE DRIVER WISHING TO SIGNAL A TURN BY MOVING THE DIRECTIONAL SIGNAL LEVER, (UP OR DOWN) MAY CAUSE THE FRONT MARKER/TURN LIGHTS AND REAR TURN LIGHTS TO FLASH IN A MANNER SIMILAR TO HAZARD WARNING, RATHER THAN FLASHING ON THE DESIRED SIDE ONLY.
Consequence & remedy
Consequence: THE DRIVER MAY NOT BE ABLE TO CLEARLY SIGNAL THEIR INTENTIONS TO TURN, CHANGE TRAVEL LANES, OR POTENTIALLY WARN OTHERS OF AN IMPAIRED VEHICLE OPERATING CONDITION INCREASING THE RISK OF A CRASH.
Remedy: DEALERS WILL REPLACE THE SUSPECT FLASHER MODULES WITH A NEW FLASHER MODULE DESIGNED WITH SEALED RELAYS AND MORE DURABLE CONTACT MATERIAL INSIDE OF THE RELAYS FREE OF CHARGE. THE RECALL BEGAN ON AUGUST 4, 2005. ISUZU BEGAN MAILING OWNER LETTERS ON AUGUST 4, 2005. OWNERS MAY CONTACT CHEVROLET AT 1-800-630-2438, GMC AT 1-866-996-9463, ISUZU AT 1-800-255-6727, BUICK AT 1-866-608-8080, AND OLDSMOBILE AT 1-800-630-6537.
04V527000 · Exterior Lighting:brake Lights
Nov 1, 2004
ON CERTAIN SPORT UTILITY VEHICLES, VIBRATION AND HEAT MAY CAUSE THE TAIL LAMP/STOP LAMP BULB TO LOOSEN IN ITS SOCKET. IF THIS OCCURS, THE BULB MAY FLICKER AND EVENTUALLY BECOME INOPERATIVE.
Consequence & remedy
Consequence: AN INOPERATIVE BRAKE LAMP WILL NOT CONVEY THE DRIVER'S INTENTION OF STOPPING TO DRIVERS IN FOLLOWING VEHICLES, AND AN INOPERATIVE REAR TURN SIGNAL LAMP WILL NOT CONVEY THE DRIVER'S INTENTION TO TURN TO DRIVERS IN FOLLOWING VEHICLES. BOTH OF THESE FAILURES CAN INCREASE THE RISK OF A CRASH.
Remedy: DEALERS WILL INSPECT THE TAIL LAMP/STOP LAMP ASSEMBLIES, AND IF NECESSARY, REPLACE THEM. THE RECALL BEGAN ON NOVEMBER 22, 2004. OWNERS SHOULD CONTACT CHEVROLET AT 1-800-630-2438, OLDSMOBILE AT 1-800-630-6537, BUICK AT 1-866-608-8080, OR GMC AT 1-866-996-9463.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
4RQ17002 · Loss Of Headlights
Opened Apr 24, 2017 · Closed Mar 29, 2021
Status: closed (inferred from source dates) · Exterior Lighting:headlights
The subject vehicles are model year (MY) 2002-2009 Chevrolet Trailblazer, GMC Envoy, 2004-2007 Buick Rainier, 2003-2008 Isuzu Ascender, 2005-2009 Saab 9-7X, 2002-2004 Oldsmobile Bravada, 2003-2006 Chevrolet SSR, 2005-2009 Buick Lacrosse, and 2006-2008 Pontiac Grand Prix. This scope includes the Trailblazer/Envoy variants: 2002-2006 Envoy XL/Trailblazer EXT and 2004-2005 Envoy XUV. The original scope of this investigation was expanded to include all vehicles equipped with the subject Headlight Driver Module (HDM). The focus of the investigation was to determine whether actions performed by General Motors adequately addressed any unreasonable risk to motor vehicle safety in the subject vehicles concerning the headlights and the HDM that controls them.Under normal electrical load and environmental conditions, the HDM can overheat inside the Underhood Electrical Center (UEC). This can cause the module to fail and result in a simultaneous loss of both low beam headlights and both daytime running lights (DRLs), often with no warning or prior detectability to the driver. This failure can be intermittent or permanent. No other exterior lights are affected. High beams, turn signals, brake lights, and reverse lights are still operational.General Motors addressed this issue with 2 recalls (14V755 & 15V519) and a special coverage program (N172091910). In view of the recalls and special coverage program implemented by GM and the vehicle high beams continuing to operate, ODI has tentatively concluded that the actions taken by GM mitigate any unreasonable risk to safety posed by HDM failure in the subject vehicles.Accordingly, the investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist. The agency reserves the right to take additional action if warranted by new circumstances.The ODI reports cited above are available for review online at NHTSA.gov under the identification numbers in the attached document.
EA07009 · Fuel Pump Module Leaks Gasoline
Opened Jul 10, 2007 · Closed Aug 28, 2008
Status: closed (inferred from source dates) · Fuel System, Gasoline:delivery:fuel Pump
DURING THE COURSE OF THIS EA INVESTIGATION, ODI OBSERVED THAT THE MAJORITY OF THE COMPLAINTS (88%) AND WARRANTY CLAIMS (94%) WERE REPORTED FOR VEHICLES THAT ARE REGISTERED FOR USE IN THE SALT BELT REGION OF THE US.THIS AREA INCLUDES 20 STATES IN THE NORTHEAST, MID ATLANTIC AND THE MIDWEST REGIONS AND THE DISTRICT OF COLUMBIA.CONSUMERS IN THE SALT BELT REGION REPORTED TO ODI THAT THEY COULD SMELL FUEL VAPORS IN THEIR VEHICLES WHILE DRIVING.UPON FURTHER EXAMINATION OF THEIR VEHICLES, THEY DISCOVERED THAT FUEL VAPORS WERE COMING OUT OF THE TOP OF THE FUEL TANK. THIS CONDITION IS CAUSED BY CORROSION OF THE RETURN AND SENDER LINES OF THE FUEL PUMP MODULE.WATER AND ROAD SALT COLLECT ON TOP OF THE FUEL PUMP LEADING TO SMALL PINHOLES APPEARING ON THE FUEL LINES.FUEL MAY LEAK AND COLLECT ON TOP OF THE MODULE AND/OR SPILL ONTO THE GROUND.THE DATA EVALUATED UNDER THIS INVESTIGATION REFLECT A RELATIVELY LOW FREQUENCY OF OCCURRENCE THAT LARGELY ARISES IN SALT BELT STATES.GM HAS EXTENDED THE WARRANTY ON THE SUBJECT COMPONENT TO TEN YEARS OR 120,000 MILES.FURTHER USE OF AGENCY RESOURCES DOES NOT APPEAR TO BE WARRANTED AT THIS TIME; ACCORDINGLY, THIS INVESTIGATION IS CLOSED.THE CLOSING OF THIS INVESTIGATION DOES NOT CONSTITUTE A FINDING BY NHTSA THAT NO SAFETY-RELATED DEFECT EXISTS.THE AGENCY RESERVES THE RIGHT TO TAKE FURTHER ACTION IF WARRANTED BY THE CIRCUMSTANCES.FOR ADDITIONAL INFORMATION SELECT DOCUMENT SEARCH.
EA04021 · Brake Lamp Failure
Opened Aug 3, 2004 · Closed Nov 4, 2004
Status: closed (inferred from source dates) · Exterior Lighting:brake Lights
GM STATES THAT SOME BRAKE/TAIL LAMP BULBS CAN PREMATURELY BECOME INOPERATIVE DUE TO MALFUNCTIONING BRAKE/TAIL LAMP SOCKETS.ON MARCH 2, 2004, GM INITIATED A 6-YEAR/72,000 MILE SPECIAL POLICY FOR 989,487 SUBJECT VEHICLES TO INSPECT AND REPLACE THE REAR BRAKE/TAIL LAMP BULB SOCKET ASSEMBLIES.ON APRIL 4, 2004, THE OFFICE OF DEFECTS INVESTIGATION (ODI) OPENED A PRELIMINARY EVALUATION (PE04-032) BASED ON CONSUMER COMPLAINTS ALLEGING BRAKE LIGHTS NOT OPERATING WHEN THE BRAKE PEDAL IS DEPRESSED.ON AUGUST 3, 2004 ODI UPGRADED PE04-032 TO AN ENGINEERING ANALYSIS (EA04-021).BY LETTER DATED OCTOBER 27, 2004 GM NOTIFIED NHTSA THAT IT WILL CONDUCT A SAFETY RECALL (NHTSA # 04V527) COVERING SUBJECT VEHICLES THAT WERE NOT ALREADY REPAIRED UNDER GM'S SPECIAL POLICY.MY 2004 SUBJECT VEHICLES BUILT AFTER AUGUST 8, 2003 CONTAIN IMPROVED BRAKE LAMP ASSEMBLIES AND ARE NOT INCLUDED IN THE RECALL.GM DEALERS WILL INSTALL THE IMPROVED BRAKE LAMP ASSEMBLY ON SUBJECT VEHICLES BUILT ON AUGUST 8, 2003 AND EARLIER.THE ACTION TAKEN BY GM IS SUFFICIENT TO RESOLVE THE ISSUES RAISED BY THIS INVESTIGATION.ACCORDINGLY, THIS INVESTIGATION IS CLOSED.
PE04032 · Brake Lamp Failure
Opened Apr 6, 2004 · Closed Aug 3, 2004
Status: closed (inferred from source dates) · Exterior Lighting:brake Lights
THE OFFICE OF DEFECTS INVESTIGATION (ODI) OPENED THIS INVESTIGATION ON MODEL YEAR (MY) 2002-04 CHEVROLET TRAILBLAZER VEHICLES.GM REPORTS THAT OTHER VEHICLES SHARING THIS PLATFORM AND BRAKE LAMP DESIGN ARE THE MY 2002-2004 CHEVROLET TRAILBLAZER EXT; GMC ENVOY, XL, XUV; OLDSMOBILE BRAVADA AND 2004 BUICK RAINIER.COMPLAINTS ALLEGE THAT THE REAR BRAKE LAMP DOES NOT OPERATE WHEN THE BRAKE PEDAL IS DEPRESSED.THERE IS NO INDICATION TO THE DRIVER FROM INSIDE THE VEHICLE THAT ONE OR MORE BRAKE LAMPS BULBS ARE NOT FUNCTIONING.GM FOUND THAT HEAT FROM THE BULB COULD DEFORM THE LAMP SOCKET, PRODUCE ELECTRICAL ARCING AND AN INOPERATIVE BULB.TO CORRECT THE CONDITION, GM CHANGED THE BULB TO A BULB THAT TRANSMITS LESS HEAT TO THE SOCKET AND CHANGED THE SOCKET TO A THERMOPLASTIC POLYMER TO IMPROVE THERMAL STABILITY.THESE CHANGES WERE IMPLEMENTED INTO PRODUCTION VEHICLES ON OCTOBER 1, 2003.GM IMPLEMENTED A SPECIAL POLICY BY NOTIFYING CONSUMERS THAT IF THEY SHOULD EXPERIENCE A BRAKE LAMP FAILURE TO GO TO THEIR GM DEALERSHIP TO HAVE THE CIRCUIT BOARD CONTAINING THE BRAKE LAMP REPLACED ALONG WITH NEW BULBS.THIS POLICY IS GOOD FOR THE FIRST 6 YEARS OR 72,000 MILES OF THE LIFE OF THE VEHICLE.ODI WILL UPGRADE THIS INVESTIGATION TO EA 04-021 AND INCLUDE THE ABOVE MENTIONED VEHICLES.