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Sister's 2003 Trailblazer Straight 6

dzrick

By dzrick
in Ask A GM Technician

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dzrick Enthusiast

dzrick

Posted
Posted

In case I was to wordy or made this too confusing.

 

The main question is what controls the idle speed when the AC or defroster is on in a 2003 Trailblazer straight 6 cylinder. I'd really like to have the defroster working in my sisters truck.

 

The rest below is just what we've done to the truck in the last couple of months in case it might have caused the problem.

 

 

This might be a little long but I want to give you all the facts as I know them.

 

Awhile back, maybe 2 months ago we had to replace my sister's battery due to a bad cell after changing it we found that the altenator wasn't charging so we changed that as well.

 

Now the facts get a bit fuzzy, she can't remember if the defroster and AC bogged the motor down before all this or not or if she doesn't know because she wasn't using either of these until recently.

I do know that until we changed the heater resistor today that she was only able to use the highest fan speed (5 I believe) but when in the the AC setting and the defroster setting would stall the truck or come close to stalling it.

 

Now she has all the fan speeds but when we put in defrost or AC it still boggs the motor down sometimes right down to a stall, it'll start right back up but I'm thinking there must be something that idles the motor up when either the defroster or AC is used that isn't doing it's job.

 

Can you tell me what it's called and where it's located or if my thinking is wrong, straighten me out.

 

Thank you for any help you can offer,

Rick

BigSilver Enthusiast

BigSilver

Posted
Posted

Your on track Rick. Definitely the idle-up feature is malfunctioning. I don't know where its located on these all electronic vehicles, other then to guess its all PCM controlled, like timing and fuel injection.

 

I'm used to the old solenoid vehicle setups. Perhaps someone else on this forum can enlighten us?

dzrick Enthusiast

dzrick

Posted
  • Author
Posted
Your on track Rick. Definitely the idle-up feature is malfunctioning. I don't know where its located on these all electronic vehicles, other then to guess its all PCM controlled, like timing and fuel injection.

 

I'm used to the old solenoid vehicle setups. Perhaps someone else on this forum can enlighten us?

 

 

Thanks for the bump and I hope someone can enlighten us soon, I may have to let her take my truck in the meantime. (don't want to) :cheers:

superjim Senior Enthusiast

superjim

Posted
Posted

There is an IDLE RELEARN procedure that you sometimes have to go thru.

I don't know how to do it.

 

Post your problem in the main forum and get a lot more feedback.

dzrick Enthusiast

dzrick

Posted
  • Author
Posted
There is an IDLE RELEARN procedure that you sometimes have to go thru.

I don't know how to do it.

 

Post your problem in the main forum and get a lot more feedback.

 

Thanks Jim,

 

I'll do that.

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