I have a 2005 Chevy Trailblazer Ext, and I have been heaing this weird noise under the hood . It is like a rumbling noise, like it is the fan scraping up against something, well it started to squek aome yesterday, and this morning when I woke up , I could not start the car, it was dead. I boosted it and drove it around a while and as soon as I turned it off all power seemed to shut off, I couldn't even boost it again, is it the alternator the battery or what????

Check the battery,to see if it has any power left. The noise you heard could have been the alternator. Auto parts stores will check the alternator for free.

Have the alternator and battery checked by a local automotive shop. Then befor putting every thing back together check the wiring that goes to and from your battery and alternator.

I have the 2003 and its been nothing but issue after issue. I dont know really where to start to unravel all the problems. The power issue started with draining all the battries Ive had installed (even AAA roadside assist.) And burnning out the right Tail lights to many time to count, after a few tickets, and new bulbs installed I replaced the whole unit (twice) Light still goes out and comes on whenever, I just never know. Many times and really most os the time If I turn HARD to the right or left...I loose power. It seem like it cutting into a valve or hose or wiring or something? Who knows? There is a ticking noise that starts and stops right after I start the vehicl, coming from the furthest back cornor right inside ...tick tick tick tick tick tick tick tick and then it just stops. Let see the front end noises...yes a few and I never figured that out it went away but now if I hit the smallest bump (markers in the center line on the road? I literally have to hurry and pull over to the side of the road and come to a complete STOP befor it will stop SHIMMY-ING and VIBRATING at the same time. I have already replaced the SWAY BAR LINKAGE KIT'S all the way around and the same issue has just returned again. I have NEVER used the 4x4 because Im affraid to 1st of all and I ve not trusted this peice of crap SUV! The FAN CLUTCH I replace just after I bought the thing and that is the ROARing noise your hearing. I got mine with a lifetime Warrentee as well as the SWAY BAR LINKAGE KITS...but who pays the LABOR this time? I am so pissed off about the whole mess that NEVER seems to END! I can keep going but Im feeling overwhelmed. Wiring seems to be Major, Ive had some senesor's replace that were in the dash but not sure what they were called. Ive replaced the Oil pan for transmission...on and on. If your having these issues Need to make complaint to Chevy. They need to do afew major RECALLS! I have also had to replace thi long shifter wire with a crap peice of plastic that holds it all together....PLASTIC that HOLDS THE SHIFTER TOGETHER! So when your car wont shift, stuck in whatever gear...that is what that is and it will run you about $175 from the dealer only! and then the labor... all you really need to replace is the crappy little peice of Plastic. Oh please I could keep going.... I paid $20,000.00 for nothing but problems that I continue to pay and pay. And I never do the interstate Hiways and never been more than and hour away from home due to issues. If your smart you'll get rid of your PROBLEM!

oh yeah I just replace the alternator after replacing the 3 battries in the last 8months, thank goodness I bought them thru AAA roadside service w a three yr garrentee. Does anyone see an issue when putting down or raising the windows---Again POWER Drops like the engine wants to die.

Its Not The Batthey! It IS THE alternator. Just went thru that. Maybe look one step past that after you replace the alternator. Have the wiring checked and computer. Oh yeah the Fan Clutch should be purchased with Assembly kit (senceor!)