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Chevrolet TrailBlazer Electrical Problems



  • My 2005 Trailblazer speedometer began registering incorrectly during a trip home on the interstate. It progressively read higher and higher speed until the needle was pointing straight down (6 o'clock position). Dealership estimated a $350 switch replacement, but a friend suggested I "reset" the system by disconnecting and reconnecting the battery. It WORKED, but I discovered the problem would return every time I used the cruise control. I decided to save the money and not use the cruise. That problem has not reoccurred.
    But since then, my gas gauge has begun registering incorrectly. After a recent fillup, the gauge dropped to empty, setting off the alarm/light. I tried the battery reset trick, but it didn't change. Any suggestions?
  • Hey guys... just thought I'd throw my 2-cents in here. Last week I started experiencing a similar issue with my 2005 Trailblazer LT. I work evenings (unfortunately, in a bad part of town) - and upon leaving my shift at 10:30 pm I noticed my headlights (and dash lights) would flicker. They never completely went off, but would pulse or flicker. Initially I thought perhaps I'd hit a rough patch of pavement, and the flicker I saw on the road in front of me was a result of uneven pavement.

    The further I drove on my route home, the more I noticed the flicker - and quickly discerned that there was an issue with my vehicle. As the lights would flicker, my battery guage would pulse or fluctuate. It varied between roughly 11-14... but only fluctuated when the lights would flicker. Immediately I called my dad, who like I - thought it was probably the alternator going out. (Typical symptoms of a faulty alternator.) Luckily I made the trip home safely... but obviously worried because had it broken down in my employer's area of town - YIKES!

    So, the next day - I take my truck into a local shop. They replace the alternator - $480 later (gulp), I'm back on the road. Don't notice anything odd for 4 days. Then LAST NIGHT, the pulsing is back. Single girl, no family for 3 states - and having been unemployed for the last year, immediately I peg the worry meter because even I (with my limited knowledge) recognize that it's probably more than an alternator issue at this point... and honestly, I'm stone cold broke.

    So again I make it to work with the incredible blinking car - and again call my dad. During my shift, he did a bit of research and found the following...

    (I have not confirmed this with a mechanic, nor discussed it with the GM Dealership - but I followed the 30-second idle warm up rule, and drove home after my shift last night with NO issues). Just food for thought... here's what my dad found and compiled into an email by copying EXACTLY what he found in various websites:

    1. Let your TB idle for at least 20 seconds before putting it into drive. This drove me nuts, as my TB had done it from the day I purchased it. Every time I took it in for service, the dealer said "cannot duplicate condition", and sent me on my way. They replaced the alternator, cleaned and tightened all the grounds, cleaned and checked the battery connections, etc. I was finally told about the 20 second idle "fix", and it seems to work

    2. "Some customers may comment that their instrument panel voltmeter is fluctuating between 12 and 14 volts on their new 2005 model year light duty full size pickup/utility vehicle.

    For 2005 model year, light duty full size pickups and utilities, are equipped with a new Regulated Voltage Control (RVC) system, covered in the September 2004 TechLink. The RVC system allows changes to vehicle voltage, up or down, under various scenarios. Battery state of charge and the vehicle’s present electrical needs are only two of numerous conditions taken into account.

    This will cause the voltmeter to fluctuate between 12 and 14 volts. By comparison, conventional systems usually maintain a more consistent reading of 14 volts.

    This fluctuation with the RVC system is normal system operation and no repairs should be attempted."

    3. Bulletin No.: 05-08-42-001

    Date: March 07, 2005

    Subject: Diagnostic Information on Headlamps Flicker or Momentarily Dim While Driving

    Models:2004-2005 Buick Rainier
    2002-2005 Chevrolet Trailblazer
    2002-2005 GMC Envoy
    2003-2004 Oldsmobile Bravada
    with 4.2L Engine (VIN S -- RPO LL8)
    A concern regarding headlamps flicker or become dim while driving may be easily mis-diagnosed. It is very important to capture as much information from the customer as possible. Below is a guideline to assist with diagnostics.

    Verify the customers specific concern.

    • What time of day does this occur (is it light or dark outside) ?
    • What driving conditions (vehicle speed, engine speed, throttle position, etc...)?
    • What was the outside ambient temperature when the condition occurred?
    • What accessories was the driver using when this condition occurred (A/C, heated seats, rear defogger, etc...)?
    • If the concern is at dusk, could it be the automatic headlamps changing from DRL to Headlamp mode and possibly back to DRL again?
    • Are there any other relevant operating conditions?

    Diagnostic Information

    • Service Bulletin - 02-06-03-008A - Info - Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output (SI Document ID #1540541)
    • Service Bulletin - 02-06-03-006B - No Start, No Crank, Battery, Batteries, Generator, Gages, SES, SIR, Brake, Security, Theft, ABS, Hot, DIC Messages, Lamp, Light, Battery and Generator Diagnostic Testing and Cadillac Roadside Service (SI Document ID #1563904)
    • Service Information - Exterior Lighting Systems Description and Operation (SI Document ID #826321)
    • Service Information - Battery Inspection/Test (Non-HP2) (SI Document ID #653410)
    • Service Information - Charging System Test (SI Document ID #1468059)
    • Service Information - Inspect for aftermarket devices that could affect the operation of the system. Refer to Checking Aftermarket Accessories in Wiring Systems (SI Document ID #816776)

    • Keep in mind high current draw items may cause a noticeable dimming of lights and a fluctuation in the voltmeter may be noted and is a normal operating characteristic of the vehicle.

    • For 2004-2005 TrailBlazer, Envoy, Rainier and Bravada with the LL8 4.2L engine only, the Secondary Air Injection (AIR) pump activation is thought to be the main contributor to this high current draw condition and is a normal operating characteristic of the vehicle. Refer to Secondary Air Injection System Description (SI Document ID #1298539).

    For customers whose driving habits tend to run the AIR pump diagnostic test that leads to concerns with the headlight flickering, if the vehicle is allowed to idle for 20 seconds prior to driving, this should allow the passive test to pass and prevent from running the active test that may dim the lights. The passive test should/will usually pass 99 percent of the time, and by allowing the 20 second idle period, it should almost eliminate the active test. Be sure to check for codes and correct related concerns if this condition repeats.

    Additional high current draw items are rear window defogger, HVAC blower motor, rear air suspension pump along with other components. For easier diagnostics, it may be possible to control or monitor these components with a scan tool.
    It is important to inspect all related connections, grounds and battery terminals for integrity . A loose or corroded connection may exaggerate the concern, and may cause other symptoms. Refer to Testing for Intermittent Conditions and Poor Connections (SI Do
  • its an indicator which tells you its time for an oil change. It must be re set everytime you change the oil.
  • its a bad connection at the battery
  • I've had this 05 trailblazer almost a year to the day and haven't had this issue this bad untill tonight. Coming home on the highway it kept losing power and almost stalled out several times. In the past its done it a little but never this badly. Had the charging system tested and they said everything was fine. I'll try this 30 second idle thing but can you reply and let me know if you have anymore problems
  • I have a 2002 Trailblazer that I've been having problems with the electrical system for a couple of years. At first the emergency lights would go on when the right turn signal was activated. This only happened when it was raining or very cold. Then the dome lights started flashing on and off a couple of times. Last December the battery died and we had it replaced by a local shop, asked about the lights and he checked it out and said he couldn't find a problem with anything. He replaced the battery again in March after numerous checks. We still have the problems with the lights and battery dying. In April we decided to take it back to the dealer ship we purchased it from. They say there is no drain showing on the vehicle but that GM has a couple of notices on the ignition and rear wiper motor cause battery drains, so we have them replaced. We didn't have any more problems until late September, oddly enough when the weather started to cool and get wet. Then the car would not start when the key was turned. Nothing, no clicking, lights, radio or anything. But if I tried again it would start right up. This happened about three times in the last three weeks and we had just decide to take it back in to have it checked out when it wouldn't start at all. This was last Wednesday. We jumped it and it ran fine again. We took it in to the dealership Saturday, explained that we had it in there back in April, what we had done then and what it was doing now. They called on Tuesday and said the battery had a bad cell and that would be the reason for the battery drain. When I asked if that would cause the problem with the ignition not starting at first then starting right up on the second try she said that she didn't think so, but there was nothing about the ignition problem on the work order so he might not have checked it. I asked to talk to the manager we talked to on Saturday when we took it in. I explained to him that I was told that the problem with the electrical was a bad cell in the battery. That the tech was not even told about the ignition. He said that the ignition wasn't the problem, that the battery drain was the major concern, so there was no reason to mention that. After going around with him for awhile he let slip that the battery tested fine on Saturday but that on Monday when they checked it again the bad cell showed up. According to him there is no way that the ignition or anything they did could have caused the break down in the battery. And that it would logical that it might be a problem with the ignition again causing all our problems. But that he didn't‘ want to replace it unless he could tell for sure and there was no way to check to see if it is bad. We are picking it up tomorrow. I didn't have the battery replaced. I'm going to have to take it to someone else. But I'm running out of options, we live in a very rural area and there are only so many repair shops around. Anyone have any ideas about what could cause the ignition to delay like it is and why would the battery suddenly go bad like it did?
    I would like to have an idea about it when I take it back in.
    Thanks, Linda
    And sorry this is so long
  • I just had my transmission replaced in my 02 and now my keyless entry device wont work and now the trunk/hatch is permanately locked and wont open, any suggestions?
  • 03 chev trlblzr, 4x4, v6. the tacometer goes dead and the truck is fine, it has no instrument lights on, nor any codes pop, the fault is intermitent. i could travel 300 miles and the tac is fine, or i drive down the block and it drops to zero, yet when i step on the gas the rpms go up to what they are suppose to read. this hasent affected any power or performance, but still am worried. i asked the dealership and all i got was dollar signs behind their eyes. i am hoping someone else has had this issue and can steer me in the right direction. i try and do all work myself on my truck, for knowledge and experience. but am desperatly seeking enlightment on this issues. if you can help you can email me at thank you.
  • tidestertidester Posts: 10,059
    you can email me at...

    Let's keep the discussion here so everyone will benefit. :)

    tidester, host
    SUVs and Smart Shopper
  • You might want to take it to a place that installs alarms such as best buy or something along those lines and see if they need to reset the alarm system or the keyless hand device. That would be my suggestion because when they replace things such as the transmission they usually have to un-do the alarm and what not. I don't know to much about cars but that is where I would start.
  • Your not alone! My wife just called me tonight while out and told me her Tach reads 7000 rpm and the oil pressure gauge reads like over 90psi. Two years or more ago the speedometer quit, and about ayear ago the fuel gauge quit! I tried countlessly to get GM to cover the speedo and they would not! So why bother repairing all this electrical if its all going to crap out like its doin. Iv been workin on my own vehicles all my life and this 2004 trailblazer is one of the worst cars i have ever driven, and have had the most electrical problems ever. When does it end! Oh yea three months ago my wifes brakes started to fade on her. After doing some investigating i found the antilock module seems to let brake fluid bleed bye therefor causing the brake pedal to fade while applying the brakes. Also had no warning light to let me know of any trouble with thw ABS system. Now i drive the car with the power disconnected to the abs system and the brakes work like preantilock systems did LOL! I never started to chase and try and fix these problem because in the end they do not affect the cars performance. I will however NEVER buy another small GM vehicle again. I own a 99 suburban with 199875 miles on it and have only done mainteance work on it. My next small vehicle will be a honda for sure, or atleast something foreign. Me being a union electrician, never thought i'd say that, but chevy has a long way to go with some of their products. If you can't tell i'm not to happy with the trailblazer. LOL ! I It is dependable but electrically leavs alot to be desired. Good luck with your quest. Let me know what you think.
  • thank you for all the info on the other issues you are having and have had...but so far my truck is over 135k and that seems to be the only issue....the tach intermitintly going keep my fingers crossed and hope that nothing else goes weird on her...but less than 2 weeks ago i finally changed the factory brake pads and still had about 20 to 25 percent left. my kids love the space and its been a reliable cross country road tripping vehicle. sorry u had these elec. issues.
  • I have an 04 Trailblazer that has an electrical problem. Every so often when you get in and put the key in the ignition the vehicle is completely dead. No lights, nothing. You cant even get the key back out of the ignition. I replaced the battery 2 weeks ago and it did it again yesterday. As soon as I hook jumper cables up, all the power comes back up and the vehicle starts fine and may not repeat the problem for a week or so. I had the starter and alternator checked and they showed ok. Any suggestions?
  • I also have a trailblazer with every electrical problem mentioned here. I have 43,000 miles and at this point, I will never buy another GM product. I purchased this new in 07, being a woman, I got screwed from the beginning. No new warranty and the extended warranty sold to me was worthless. Everything from sensors to battery going dead for no reason has happened. Now my oil pressure gauge is all the way to the right, oil is fine. I took it to a dealership and was told about 600.00 for repairs. Luckily a friend of mine took pity on me and found out it is the oil sending unit that has gone bad. $33.00 for the part and about 2 hours of labor. I also have had every gauge in the dash quit at one time. I have replaced the battery 2 times and every other week the service 4 wheel drive light comes on for a day or so.
  • Mine done the same thing, a friend of mine replaced a sensor and it hasn't done that sense.
  • :lemon: i have a 04 chevy which has been nothing but problems i swear the car is posessed. i get in after the car sits all night and it wont start so after 10 tries it starts right up. i thought it was the started after almost a and lots of visits to the car repair place chevy yesterday finally let me know that this is a common problem and its the ignition switch and i was happy until im told that this is on back order nationwide thats right nationwide so yes im on a waiting list for this part who knows when this will be available finally the truth how this switch turns the lights on and off in the car and dashboard also stop the car mid way while turning then you have to shut the car off and back on to get to go....but that not even half of what i went through with this truck ...i cant understand if a part is on backorder nationwide why not put a recall on this part its obviously a problem in 98% of the trucks!!!! yea but who am i lol :mad:
  • bsk29bsk29 Posts: 1
    I am having several problems with our 2005 Chevy Trailblazer, can someone help?...It started with headlights dimming at night, then when you start the car the powered locks go crazy clicking for about 8-10 seconds, after filling the vehicle up with gas the gas gauge went to empty and finally would not go into 4 wheel drive. My husband took the vehicle to Autozone to have them test the battery & alternator, which both tested good. Anyone have any suggestions?...Also wanted to add the car starts fine.
  • mah208mah208 Posts: 6
    I also have an 04 Trailblazer that I got used last year 09. It had only 21000 miles and I have the exact same problem as you. The vehicle is completely dead, but when I hook up cables it starts right up. Battery is now new and vehicle checks out okay. Did you ever find out what the problem was. I am totally confused. Any help would be greatly appreciated. Thanks
  • mah208mah208 Posts: 6
    I have the same problem as [knickles], what sensor did your friend replace. i am at a loss.
  • I have a 2004 trailblazer and first thing that happened was while making a left turn a few days ago my car completely shut off. Started back up again fine, a few days later and I cannot get my key out of the accessory mode position to take key out of ignition. Any ideas?
  • I have not experienced the problem with the left turn. However, when I experience the electrical problems aI mentioned, absolutely nothing turns on, I could not pull my key from the ignition. I was told by a local mechanic that the ignitions switch actually requires a trickle of power to release the key. Just putting the charger on the battery for a few seconds was enough to cause the release.
  • Sorry for the delay in getting back. My trailblazer is currently working fine (fingers crossed). Both times these problems occurred I tried everything I could think of to trace the problems. The only bit of information I could wiggle out was when the car was dead the battery measured seven volts. A very quick jump or only a couple of minutes on a charger and the car started right up.The first time it happened was with a battery warrantied for eight years that was two years old. I replaced it with the same model battery and experienced the same problems a year or two later. I brought the car in to a dealer for that and the window electrical problem (which was fixed by replacing the window control switch for $450.00). They tested the battery and told me it was defective.

    I drove the car to the battery seller and showed them the test from the dealer. They ran some sort of battery test five times. The first four times it passed but it failed the fifth time. With that they replaced the battery for free.. So once again my problems have disappeared.
  • frzdawnfrzdawn Posts: 15
    hi yes i finally took it to chevy and they told me it was the ignition switch yes this part is on backorder they had to request it from all dealers threwout the 50states the part came in about a week and a half later and i paid 270.00 for a 40$ piece yea :( but the good news is the car has not done that since this should definatly be a recall they did no testing or anything and know right off that was the problem hope this helps ;)
  • frzdawnfrzdawn Posts: 15
    sorry i didn t have the key stuck problem but i did have the when i was turning the car completly stopped but in my conversation with the chevy tech says that the ignition has something to do with that problem says that it messes with the clutch and it also turns the lights on buy itself that ignition switch causes lots of problems... :sick:
  • mah208mah208 Posts: 6
    Thats for the information. I am going to try to get the ignition switch fixed...hopefully that will fix my problem. Thanks for getting back to me.
  • mah208mah208 Posts: 6
    thanks for getting back to me. I need all the information and help i can get. I had the same thing with the battery, and now have a new one. I am also going to try to get the ignition switch fixed. Here to hoping it works.
  • Recently, while driving my passenger side front window went down by itself, then up again, all in short little bursts. Happens occasionally. Then my rear passenger side window went all the way down in one burst the other day but it happened just that once. Yes, I powered it back up fine. It's a 2002 Trailblazer. Any suggestions? Thanks.
  • Other than not doing things by itself my shotgun window did the same thing. It would happen no matter which window switch was used, the driver or the passenger. After a few months of frustration the window mostly stopped working. Does the illumination in the switch at night come and go? Mine did and when it was off nothing on the door would work, even the electrical lock.

    Turns out it was all due to a bad window control switch. I don't know where it is located but it cost me over $400 to get the dealer to replace the switch. Since then I have not had any problems.
  • Monday the 15th started real sour for me. I've recently gone over 70K miles in my 06' Trailblazer Ext. Around 5 or 6 months ago I had it in the shop what I recall was a crankshaft sensor that went out. Everything has been riding just fine on the vehicle. We did take about 100 mile drive on Saturday and it sat in the garage all day Sunday and overnight. Monday morning the garage was full of smoke and smelled like something electrical was burning. I figured it was my garage heater and shut it off. As I went to get into the car the doors were all locked and none of the remotes were working. I manually unlocked with the key (who does this anymore??) and there was no power to the trailblazer. She wouldn't turn over, nothing, dead, and, it wouldn't give me my key back (although I hear this happens on a dead battery). I popped the hood and it was scorched inside. I had it towed over to the GM shop and am awaiting the word on what happened. I am concerned due to the fact the car was parked for over 24 hours and while sitting there something caused it to burn up. Any thoughts? GM Mechanics seemed puzzled.
  • burdawgburdawg Posts: 1,524
    What exactly was burned? The electrical harness? Or something else?
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