Chevy TrailBlazer Climate Control Questions

dwaynez28dwaynez28 Member Posts: 2
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.


  • garyfirstgaryfirst Member Posts: 1
    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 Member 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.
  • ejurikejurik Member Posts: 2
    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 Member 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 Member Posts: 27
    could also be a mode actuator...small motor that opens and closes flaps in the vent assembly to control where air goes
  • tursiopstechtursiopstech Member Posts: 1
    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 Member 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 Member 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?
  • jeremymasseyjeremymassey Member Posts: 1
    My 2002 Trailblazer is doing the same thing, does any one know what is going on? Please help.
  • nedtnedt Member Posts: 2
    I am having the exact same problem withe the climate control-- Any answers ?
  • warddwardd Member 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 Member Posts: 2
    Replaced ambient outside temperature sensor-- seemed to do the trick--Part was about $20
  • burdawgburdawg Member Posts: 1,524
    Do you have the part # for the sensor? I've been looking at GM Parts Direct but can't find it.
  • al55442al55442 Member Posts: 1
    Can you tell me what the cost was for the repair? Did you repair this your self ?

  • chrisneedshelpchrisneedshelp Member Posts: 1
    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 Member 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.
  • mtt2002mtt2002 Member Posts: 2
    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?
  • mtt2002mtt2002 Member Posts: 2
    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?
  • jerrcribjerrcrib Member Posts: 21
    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
  • jerrcribjerrcrib Member Posts: 21
    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 Member 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 Member 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 Member 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 Member 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 Member 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 Member Posts: 40
    Thanks!! Will pass this on to my mechanic and hope it works!!
  • moe81854moe81854 Member 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 Member 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 Member 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 Member 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
  • gorilla2gorilla2 Member Posts: 1
    has their been a issue with the fan speed controls? is their a resistor pack? i have a 2004 with only 2 thru 4 working.
  • traveler73traveler73 Member Posts: 5
    when air is on condensation leaks all over floor from underneath dash ---has anybody had this happen/ know what it is?????--thanks!
  • lrs1018lrs1018 Member Posts: 2
    I opened glove box and i see nothing but fan motor. How do i pull radio and control modulator out because i see no actuators to spray any wd40 onto, ( where are the vent flappers) this all sounded easy till i opened glove box and looked inside.
  • jerrcribjerrcrib Member Posts: 21
    drop glove box to floor look to your left under dash just spray the wd 40 into this area it will coat everything,it will not hurt electrical components. You will not be able to see what you are doing. First actuator is to your immediate left. To change control modulator you will have to remove all the trim from front of dash,it is all one piece,it is really not that hard to do, You can the get to modulator radio speedometer cluster. To get to middleactuator,etc. you will have to pull completetop of dash out. I would not recommend you doing this.If i can help you more let me know. Jerry
  • jerrcribjerrcrib Member Posts: 21
    control modulator gm has always had a problem with this, no way to repair different components, all one piece about 160.00 from ac delco gm parts on line
  • cjoyce01cjoyce01 Member Posts: 2
    My a/c has been running cold but only for about 30-40 minutes and then the air blows warm. I don't know if this is a normal service issue or does it mean there could be a leak? There's nothing in the owners manual for servcing the a/c.
  • jerrcribjerrcrib Member Posts: 21
    something is cutting out power to the a/c clutch,clutch sensor switch or low pressure switch. check freon first but if it cools for that long I would say the freon is okay no leak. I have a 2002 trailblazer and have had this problem off and on for 7 years dealer never found the problem under warranty. The next time it quitscooling pull over cut engine off and start up again to see if it starts cooling again. jerry
  • cjoyce01cjoyce01 Member Posts: 2
    Thanks Jerry! I'm going to a dealer tomorrow but I don't want them running up my bill for stuff I don't need, i.e. freon. I'll try your suggestion. At least I feel armed with knowledge for tomorrow. Thanks again!
  • shutterbshutterb Member Posts: 1
    Where is this sensor and what does it look like? I see a small two wire sensor just in front of the radiator. is that it?
  • pa2tx2mdpa2tx2md Member Posts: 1
    I am having the same problem with my 2003 trailblazer. The external temperature reading fluctuates, starting out at 50 degrees and staying there until it eventually corrects itself. Then it may go back to 50 degrees. The internal air comes on full blast as the external temperature reading rises rapidly to read the actual outside temperature. Did replacing the ambiet outside temperature sensor resolve the problem. Is it something that a dealer has to do or is it a relative simple fix? Where is the part located?
  • burdawgburdawg Member Posts: 1,524
    The easiest way to replace the ambient sensor is to remove the grill. It's mounted under the top radiator frame rail, a little hard to see, but if you follow the wires you'll find it. You have to push the plastic snaps back to get it out of the hole. I went to the dealer for the new part, the earlier style has been discontinued and replaced by the later style, but it's the same part on a plastic bracket. You remove the sensor from the bracket, throw the bracket away, and push the new part into the existing hole (it just snaps in).
  • aopimeraopimer Member Posts: 5
    My trailblazer is doing the same thing. Do you know the part #? Is this something that has to be purchased through a chevy dealer?
  • aopimeraopimer Member Posts: 5
    Do you know the part number of this sensor? It is way too hot to be dealing with no a/c. Thanks.
  • jerrcribjerrcrib Member Posts: 21
    no I do not know the # I have not had to change mine
  • aopimeraopimer Member Posts: 5
    I've replaced the ambient sensor, but it's still reading in the 40's & 50's when it's 90 degrees outside. Any ideas? Please help! :confuse:
  • james107james107 Member Posts: 3
    Found a fix yet?? I have the same issue with my 02 Trailblazer. Replaced the sensor, still reads at 50 degrees. One odd thing, while going to get the new sensor, I just left old one hang, and it worked for about 20 minutes then nothing again.... Even after new one put in, still nothing.
    Let me know if you found the cure, drop me an email even at [email protected]

    Thanks. Jim
  • aopimeraopimer Member Posts: 5
    Mine was working off and on for a few months. I finally bought the new sensor. When I replaced the sensor, nothing changed for about 1 1/2 days. It still continued reading 50 degrees and sometimes lower. After that, it has worked without a problem. I don't know if the computer had to reset, but it works now.
  • james107james107 Member Posts: 3
    Thanks much for the info. I put the new one in, but didn't wait very long for results, and took it back out an returned it, as was 22 bucks, but am going back an get it, and plug it in and give it a chance.

    Thanks again, jim in Ohio.
  • burdawgburdawg Member Posts: 1,524
    That sensor is nothing more than a thermister. Consequently any resistance in the contacts in the connector will affect it's accuracy. Make sure there's no corrosion, dirt or other contaminents in the connector.
  • james107james107 Member Posts: 3
    I figured it must be some sort of variable resistor, and am guessing it is accross the ground line, thus do not see power at the connector.
    I did spray it with contact cleaner, but am going to double check again when i get the new part, which is tomorrow, takes 3 days to order an get it in at Auto Zone.

    Thanks Jim, Ohio
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