Hi guys,
I really don't know anything about how AC and Heaters work, so I apologize in advance if I'm asking a silly question. For the last two weeks I've been have a problem with my AC. I turn on my AC and it blows ice cold, and then all of a sudden it starts blowing out very hot air...basically it switches to heat. Sometimes it will be stuck in heat for a few minutes and then back to AC....and then back. Sometimes it just gets stuck in heat and stays there. I know that it's not that my AC is turning off and hot hair is just coming out...it's actually like if I turned on the heater!... I don't know what to do but it's almost impossible to bear when it's 95 degrees outside and my AC decides to be a heater.

Can anyone think of why this may be happening? I read some other threads, but in those threads the temp was stuck in heat....mine goes back and force. I'm really going nuts and I have a 2 year old baby to boot.

Any help would be REALLY appreciated.

Thanks

 

You most likely have a broken plastic gear on the actuator, that opens and closes a door inside your dash. If you have the automatic climate control, the cheapest I have found is about $100. I am currently searching for a replacement gear for mine. I really don't wanna spend $100 for a simple plastic gear. I am also trying to just epoxy the gear back to the aluminum shaft it presses into. I hope you have small hands or a big wallet, stealerships want an arm and a leg to fix it. It is located behind the glove box opening in a very tight location behind the vacuum switch with the lever coming out the right side.

I just found this forum and haven't had a chance to search it, but you asked one of the most common questions on any s10,sonoma,blazer,jimmy forum I have read. I am surprised not to have seen any of the common flames to your question, so perhaps this is why nobody answered you. If you actually search for it you will find detailed tutorials on this repair. If not on this forum, others for sure. Automotiveforums has Blend Door (with pictures and the common problem).

 

Hard to answer that one clearly. If you're getting cold air sometimes the blend door could be OK? Could still be worth checking though. I helped a friend change one in his S10 pickup (bitch of a job, as TRTl says, you need small hands) & I seem to remember that as well as the motor there was some wiring coming from it that told the computer what position it was in. Do you have the computer climate control? If you have it could be one of the temperature sensors has gone bad & is sending erratic signals back to the controller.

 

What mine does is continually switch from hot to cold because once the shaft turns the door all the way it slips inside the gear. The computer apparently cant figure out if the door is open or closed. The broken gear holds tight enough to the shaft to still move the door, but not tight enough to tell the gears to stop spinning. A 1/4"wrench and 7/32 bit (I believe that was the size) attached to each other and held in place with a rubber band (or a hair tie if you happen to have a ponytail while doing it) will be your best friend in this situation. It is a very tight fit, and expect scratched hands if you aren't quite the petite person. I can't guarantee this will solve your problem, but it is apparently the cause of at least part of mine. Once I get everything back together and sorted out I will know for sure,about mine. If the epoxy doesn't work I intend to try and find a replacement gear, as i am fairly certain my actuator will work once the gear is repaired. I am just very reluctant to spend upwards of $100 on a small plastic gear that cant cost more than a few cents.