Truck dies when heater or A/C is on

[Btbabies]

I have a 2003 Chevy trailblazer. My problem is when I turn on the air conditioner or the heat the car shuts of. If I turn it on while I'm driving it will stay on but once I'm in idle it shuts off. Please help
Thanks.

[ProTech]

Very common problem, and a very simple fix. You need to clean out your throttle body. What has happened is that there is excessive carbon build up on the throttle blade and the entry path for the air into the intake manifold. This basically lowers your idle speed since it can't get the needed amount of air. Once an additional load is placed on the engine, such as turning on the air conditioning, the engine will stall out.

A thorough cleaning of the throttle body will solve this problem and get you back up and running like normal. You would need to remove the intake duct work, and then once you have access to the throttle body, clean it out with a good parts cleaner or 'brake clean'. Use a rag to get all in and around the throttle blade and throttle opening. You'll see how black it is once you remove the ducting. Hold open the throttle blade so you can get inside good.

After you're finished, reinstall everything and then fire it up. Let the vehicle idle for a few minutes. It may be unstable, but this is just the computer 're-learning' the idle speed again. After a few minutes, take it for a drive around town. Once it seems to be running normal again, go ahead and turn the air conditioning back on and you'll notice it won't die out.

[crisp90]

That thread is nicely put for asking. This issue also come in my chevy and it can be resolved.

[carriedi]

If your problem is the same as the first post then cleaning your throttle body where the throttle plate closes could solve your problem. dirt will collect on the throat and the throttle plate and close up the passage where air gets through. Your computer controls your idle and will make the Idle air valve open to compensate. When enough time goes by, the amount of air blocked off at the throttle body will be so much that the computer may not act quickly enough to keep the engine running. Cleaning the throttle body (the throttle plate and bore and the Idle Air Control, IAC) will restore the volume of air to lower the amount of work the IAC has to do.