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Chevy TrailBlazer Climate Control Questions

Son jumped another car,using mom's 2003 Chevy Trailblazer, blew a 125 amp fuse under hood to fuse block, replaced fuse,everything appears to work except the A/C blows only to the floor and not out the main dash vents,have check fuses, swapped around other like relays. I know its probaly simple fixs, but i cant find it. Thanks.


  • About a two weeks ago my heater control for the fan will only work on no.4 and 5. An i have a engine noise that gets louder everytime i get hit the gas. I've ruled out the alternater and i took the surpintine belt off an start it. It's quite like it should be. I've been driving it for a year and three months.
  • tomcincytomcincy Posts: 5
    I've just recently experienced the same problem except mine started with no. 1 and 2 going out followed by 3 and 4 a few weeks later. I'm now left with 5 or nothing. The same thing has happened with my sister's Grand Prix of the same year which leads me to believe that there is a defect in the control and it's not an isolated occurance, have you learned anything more?
    I've also had problems with a "sqeak" somewhere in the suspension and both of my rear speakers stopped working at the same time.
  • Hi guys. I have trailblazer 04 (purchased new). First 2 years and 50,000 miles - now problem. After that:
    Engine start stoling now and then, few weeks later engine dyed on the highway @65MPH while towing the boat! Imediately lost of power stering, power breaks! I managed to stop and after few atempt started again and get lackily get home with constant power jump and few stoling. Went to dealer twice: first they replaced crank shaft actuator $550, next day(car stoling again)they replaced o2 sensor=$150! After that no more stoling but: 1 week later while changing the speed of the ac/heating fan it stop working and the same moment hapen foloving: ABS light-on;brake light-on;4WD light-on; cruise control not working; ilumination of driver door butons not working; unable to change the direction of air blow. NOW - after 10 -20 minutes of driving everything goes to normal until i stop and restart the car!!!??? I have been in service with this problem about 5 times, spent $1,250 (replaced 1 computer module)and theproblem is stil there???!!!
    Thas enyone have any idea what to doo? Please and Thank you.
  • jwoodiejwoodie Posts: 16
    Could be internal breakdown in the blower control module, located beneath the right side of the instrument panel next to the blower motor. The part number for an updated blower motor control module is 93803636.
  • jworkmanjworkman Posts: 27
    could also be a mode actuator...small motor that opens and closes flaps in the vent assembly to control where air goes
  • Can get defrost and floor vents, but cannot get dash vents on a 2002 Trailblazer. Leaning toward the Mode Actuator, but not sure. Just adding another observed case tot he list.

    - TursiopsTech
  • dwaynez28dwaynez28 Posts: 2
    Hey guys,thanks for your help, in my case it turn out to be the actuator, wont let my son's friends jump off their car anymore. Dwayne
  • bquebbqueb Posts: 1
    I have never had any problems with my 2002 Trailblazer LTZ until now. All of a sudden, the External Temperature reading fluctuates. It usually starts and stays on 50 degrees, and then sometimes eventually gets up to correct temp, then may go back to 50, and so on. This morning, it started off correctly, then all of a sudden, went to 17 degrees, which caused the heater to turn on, since thermostat set to 72.

    Has anyone else had this problem, and what did you find out, and how much did it cost to correct?
  • My 2002 Trailblazer is doing the same thing, does any one know what is going on? Please help.
  • nedtnedt Posts: 2
    I am having the exact same problem withe the climate control-- Any answers ?
  • warddwardd Posts: 1
    Same problem. Mine goes down to -66 degrees F when it's 100 degrees outside. If anyone gets a lead on this please let me know.
  • nedtnedt Posts: 2
    Replaced ambient outside temperature sensor-- seemed to do the trick--Part was about $20
  • burdawgburdawg Posts: 1,524
    Do you have the part # for the sensor? I've been looking at GM Parts Direct but can't find it.
  • Can you tell me what the cost was for the repair? Did you repair this your self ?

  • I have a 2003 Trailblazer and my heater control stopped working on 1 and 2 then a month later on 3 now it just works on 4 and 5. Have you found any resolve for this?
  • tblazedtblazed Posts: 945
    Probably the blower motor resistor has failed. It's up behind the glove box and blower motor, and is relatively easy to get to once you remove the passenger side lower kick panel and lower the glove box down by releasing the stop.
  • I have a 2002 Trailblazer that the heat only works on the passenger side. No matter where the driver temperature lever is set, the heat blows cold on the driver side. I am told the left heat sensor need replaced. My question is: Where is the left heat sensor located and how do you replace it?
  • Reference my post: Trailblazer heat blows cold on the driver side.
    Now the dealer is telling me the heater control module needs replaced. To do so he claims the dash and steering column need to be removed which is why they want $600 to do the job. Does this sound right? It seems you should be able to pull the part of the dash that surrounds the radio, climate control, and instrument cluster without the steering column. I assume the heater control module is located behind the climate control levers. Is that correct?
  • 2002 chev. trailblazer,heat and air control works and the doesnt work on vents selected, then sometimes no dash vent,switch vents get a steady clickin noise in dash. I guess from vent control switch? any help would be appreciated
  • can anyone tell me where the actuator air inl. vlv is on a2002 trailblazer.this may be my problem with small volume of air out dash vents.thanks
  • moe81854moe81854 Posts: 3
    I have a 2003 Trailblazer I am having problems getting heat to come on takes 10 to 15 minute or until car get to 150 degrees before the blower fan starts and I get any heat on any setting.
  • ticadooticadoo Posts: 40
    Just purchased a 2003 Chevrolet Trailblazer, extended, loaded. Only cold air will come out of passenger vents. Dealer had for over a week replacing motor and acuator. Just got truck back...still doing the same thing. Any suggestions? Thanks
  • jerrcribjerrcrib Posts: 21
    I changed control modulator on my 2002 trailblazer.part about 150.00. Then I sprayed wd 40 inside under dash on all vent controls etc. fixed my problem
  • ticadooticadoo Posts: 40
    Thanks for the info. Mechanic supposedly replaced modulator; then realized the "acuator" (not sure of spelling) was bad, which was thought to have caused the modulator to go bad. After replacement of both, I still only get cold air out of passenger side. Do you think the "magic charm" was the WD40?
  • jerrcribjerrcrib Posts: 21
    I know that it worked for me, after I changed control modulator,I still had vent problems. After I used wd-40 on all interior parts,flapper etc. I have had no more problems. jerry ps I believe the flapper valve was sticking
  • ticadooticadoo Posts: 40
    Thanks!! Will pass this on to my mechanic and hope it works!!
  • moe81854moe81854 Posts: 3
    were is the acuator located and the heat sensors on a 2003 trailblazer ext 4x4 located i put in a new control module and it still doesnt come on till temp gauage is 150 or higher some times and if i shut the truck off and turn it back on it still doesnt come on i thought the fan motor should come on when you put defroster on can any buddy help me
  • ticadooticadoo Posts: 40
    I had modulator, accuator and some heat fan thing (behind dash) replaced on my 2003 Trailblazer due to heat coming out of drivers vents, but only cold air out of others. I now have heat, but it does not blow like it is supposed to. Now, my A/C doesn't work nor does the rear heat or A/C work. Is there any end to these problems?
  • lrs1018lrs1018 Posts: 2
    Having problems with a/c vent control on 2003 Trailblazer. Back vents work fine, nothing in front but a little out of leg area. I see quite a few have same problems. Where is modulator located and how do you get to vent flappers to put WD40 on them? Any help will be greatly appreciated.
  • jerrcribjerrcrib Posts: 21
    control modulator is where you turn on your a/c and heat,middle front, you then have actuators for each vent flapper,I would say it is the main control modulator. To spray wd40 into flapper vents go up under dash at glove box, glove box snaps right out, spray up into left side toward steering wheel,turn air off and on and different settings. good lucl jerry, ps try the wd 40 first
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