How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask stin1974 Your Own Question
stin1974, Transmission Tech
Category: Chevy
Satisfied Customers: 765
Experience:  Chevy Transmission Tech
Type Your Chevy Question Here...
stin1974 is online now
A new question is answered every 9 seconds

2003 Chevy Trailblazer LT: 000 miles..battery mechanic

Customer Question

I have a 2003 Chevy Trailblazer LT with 62,000 miles. The oringal battery died and I replaced it with a brand new one, same type and volts. When I left my mechanic I noticed that the idle dropped lower then usual when I stopped at a light. I then turned on the A/C and no cold air would blow out of the dashboard vents! Cold air was blowing out of the defroster vents on the front windshield,floor vents,side window vents and the rear A/C vents.I tried moving the control knob around to all positions and all fan speeds but no change.My mechanic said maybe it was the computer and the A/C would reset itself in a couple of days.I asked a service manger at a Chevy dealer and he said it has nothing to do with the battery change and it was just a coincidence .Can you tell me who I should believe and how do I fix this problem? Sweating it out in NY!
Submitted: 8 years ago.
Category: Chevy
Expert:  stin1974 replied 8 years ago.
Are your heat and air controlls electronic?
Customer: replied 8 years ago.
I dont think so. I would I know for sure?
Expert:  stin1974 replied 8 years ago.
I just meant if your gages for it are lights instead of knobs. Like climate controll type lights, if youve ever seen them.
Customer: replied 8 years ago.
I push in a button to engage the A/C and it lights up. I also push in a button to engage the recycled air flow and that lights up. I adjust the speed and vents with turning the knobs.
Expert:  stin1974 replied 8 years ago.
Have all of the fuzes been checked?
Customer: replied 8 years ago.
Expert:  stin1974 replied 8 years ago.
I would chech all of your fuses being that the battery was just changed. And if your mechanic said it was a possible computer problem, well , the computer runs off of electricity (the battery) so anything is possible as far as bumping a wire or shorting out something when removing it. But who can say for sure. But, as I said I would check the fuses first.
stin1974, Transmission Tech
Category: Chevy
Satisfied Customers: 765
Experience: Chevy Transmission Tech
stin1974 and 3 other Chevy Specialists are ready to help you
Expert:  Steve replied 8 years ago.


This is NOT a fuse or power supply issue, if the control head is lighting up at all. Also, neither the vehicle's powertrain control module (drivetrain computer) nor body control module (body computer) is involved in HVAC airflow operation so neither of these components can be the source of your problem.

Your problem is most likely an internal problem in the control head assembly. To determine this for sure, a Vetronix Tech-2 scan tool will be required to check the operation of the control head and it's ability to communicate on the vehicle's data network.

It does not matter whether the system is manual or automatic control; the same problems occur with both versions. The affected components were used in production on vehicles built between mid October 2002 and January 2003. If your vehicle was built within this date range (date of build will be on a label inside the driver's door jamb area or on the drivers door) then yours has one of the control heads that has some serviceability issues. Part numbers of the affected control heads are 15202099, 15202100, 15202101 and 15202102.

These particular control assemblies can lock up and become non functional if they receive a voltage spike (such as when disconnecting or connecting a battery cable or by jump starting the vehicle). They are also not able to be programmed at a GM dealership with new software, or they lock up and stop operating (see GM technical service bulletin #03-01-38-003).

To determine for sure if the control head has become inoperative, you will need to take the truck in to either a GM dealership or to an independent shop that has a Tech-2 scan tool to have it checked. Replacing it with a new one also requires the Tech-2, to install the correct software calibration for your vehicle or it will not operate, so I am afraid this is one of those things you cannot fix yourself at home in the driveway.

I hope this is helpful; if so, please click my accept button... thanks!

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Previous | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland

Meet The Experts:

  • GM Tech (Cam)

    GM Tech (Cam)

    Chevy Technician

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years experience.
< Last | Next >
  • GM Tech (Cam)'s Avatar

    GM Tech (Cam)

    Chevy Technician

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years experience.
  • Tim's Auto Repair's Avatar

    Tim's Auto Repair


    Satisfied Customers:

    Have owned a repair shop for 25 yrs.
  • Gary's Avatar


    Chevy Technician

    Satisfied Customers:

    15 years GM master tech
  • Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    ASE Master Certification. GM World Class Certification
  • John's Avatar


    Master A.S.E Automotive technician

    Satisfied Customers:

    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • Don 'Mo Lurch''s Avatar

    Don 'Mo Lurch'

    Auto Mech / Electronics

    Satisfied Customers:

    Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.
  • Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    18+yrs experience. State Inspector and Chevy Diagnostics