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2003 Malibu heater temp on full?!?!

11K views 11 replies 6 participants last post by  DrivenDaily 
#1 ·
a few days ago my heat decides to stay on the highest temperature, just in time for summer. Even when I turn the temperature dial all the way to cold, AND turn on the A/C, it still blows HOT air. I can turn off the blower fan, but driving on the highway still forces hot air into the car. Anyone have any thoughts about this?

Thanks!
 
#2 ·
You've posted in the Gen5&6 area. What year and model do you have? What engine? Do you have Automatic Climate Control?
 
#4 ·
I have the same problem as well with my 2003 V6.

To further make it interesting. I replaced the entire switch cluster for the climate options today and the problem did not fix itself.

Something I noticed, that may need some digging on my part, or someone else's experience, is that the heat control is actually driven through some form of vacuum hose/air hose. It is not resistor based at all. I may try to trace the lines to see what's going on but I'm not sure how far under the dash they go.

Further compounding things, even with a new switch I am unable to use fan settings 1,2,3 only 4,5 work without issue.
 
#5 ·
I may try to trace the lines to see what's going on but I'm not sure how far under the dash they go.

Further compounding things, even with a new switch I am unable to use fan settings 1,2,3 only 4,5 work without issue.
They go all the way to a vacume operated little "motor" that moves a damper to select heated or cooled air. It is likely that the motor has failed or the damper is jammed. It is possible that the hose has pulled loose.......but I think the motor is inside the air ducts and is hard to get to; very hard.
There is another owner on here who is going through something similar.
Last post, I think he was still contemplating his next move.

If you got a new fan speed selector switch with the new panel, then either the motor is bad or some wires are broken........which is a different problem.

Replacing parts on a guess often turns out to be expensive and time consuming and frustrating. Good luck.
 
#6 ·
Just found a potential solution to the fan speed. There is a blower resistor pack, which, while not easy to replace, is user replaceable, and has a tendency to go bad on these cars for some reason. Pain to get to though.

I'm about 1/4 the way into ripping the dash apart to track the air lines from the switch. I doubt I'll get to it this weekend but the new cluster at least lets me turn on the recirculate so I don't get pure hot air as I drive down the road.

I can't afford to go have a dealer or someone fix either issue. So I will get a solution for it. Just give me time.
 
#9 ·
I'm about 1/4 the way into ripping the dash apart

I can't afford to go have a dealer or someone fix either issue. So I will get a solution for it. Just give me time.
It sounds like you are being deliberate and careful but tearing into the dash on a modern vehicle can be a costly and sometimes dangerous undertaking if you make just one tiny mistake and set off an air bag, for instance.

Good luck with your project; keep us posted.
Others may find your experiences educational.
 
#10 ·
I have read that this issue is caused by the air blend door motor failing OR the temp controller on the instrument pack failing. I guess the actuator motor is in behind the glove box and the entire dash doesn't need to be removed to get at this. I am going to buy a new control pack and actuator motor.

I took apart the instrument pack and all vacuum hoses seemed to be working properly. There are a few on the dial for each ZONE and then two other hoses for interior and exterior air flow..... apparently the HOT/COLD air is controlled solely by the dial and air blend door motor. If anyone knows for sure otherwise, I appreciate any and all insight!

tks,
 
#12 ·
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