99 blazer ac goes cold hot cold hot cold

[unit1]

I have a 99 blazer with climate control that the ac system is working but something to do with the climate control is switching it back and forth. As it blows cold for about 5 second then hot then back to cold. back an forth back and forth. this seems to be a common problem as i have found a couple of post on it but no one list for sure what finally fixes it. i can see the temp. actuator on top of the ac box ( behind glove box) switching back and forth. So i know this is related directly to me problem. Does anyone know if this actuator is my problem or is it another sensor that is telling it to do this. Any help would be greatly appreicated as i dont want to buy this 130 dollar actuator and it no be the problem. please help

[MT-2500]

Originally Posted by unit1

I have a 99 blazer with climate control that the ac system is working but something to do with the climate control is switching it back and forth. As it blows cold for about 5 second then hot then back to cold. back an forth back and forth. this seems to be a common problem as i have found a couple of post on it but no one list for sure what finally fixes it. i can see the temp. actuator on top of the ac box ( behind glove box) switching back and forth. So i know this is related directly to me problem. Does anyone know if this actuator is my problem or is it another sensor that is telling it to do this. Any help would be greatly appreicated as i dont want to buy this 130 dollar actuator and it no be the problem. please help

There is a recalibrate procedure is somthing has been changed or if battery has been disconnect or changed.
But first make sure it is full of freon and get a good engine /body pcm capable scanner on it and check computer system and check for body coes and post back any body codes.
MT

[RJ MALIBU]

[If your R-134 refridgerant is low your compressor will not properly or fully enguage which could be another solution to your problem. Also if you have low refridgerant you may have a leak(duh).

[unit1]

hey checked freon and it is good. i dont know of any one with a good scanner that will read body codes other that taking it to the dealer ship. is there a temp sensor that tells acutator behing glove box with to turn or is it built in to the actuator or the control in the dash. has no one ever heard on one doing this.

[MT-2500]

Originally Posted by unit1

hey checked freon and it is good. i dont know of any one with a good scanner that will read body codes other that taking it to the dealer ship. is there a temp sensor that tells acutator behing glove box with to turn or is it built in to the actuator or the control in the dash. has no one ever heard on one doing this.

There is 6 actuaters on it.
The air mix door is controled by AC module. It has a potentiometer on it that tells the AC module where it is then the AC module tells it where to go or where it wants it.
AC module may have lost it mind or got a static charge.
Recalibrtate it.
Ign off remove insturment panel fuse 15 amp RDO/BATT fuse for a minute.
Install and turn on ign.
The air mix door should cycle threw full hot and full cold position.
Give that a try and post back what it does.
Has battery been disconnected or jumpered or ran dead?
Any flashing lights on control panel.
Put a air cond low and high pressure gauge on it and post back the low and high pressure at idel and at 2000 rpm with compressor running.
MT