1997 Buick LaSabre Heater Control

[Debbie Mars]

I have a 1997 Buick LaSabre and as of the last few months my heater will not blow very warm air. I have had the heater core flushed and I have replaced the thermostat. Still it doesn't blow warm air. Also the AC does not blow cold air. The compressor kicks in but the air does not get cold. Could it be the lever that slides back and forth from warm to cold not working. Is it electronic, mechanical, or vacuum activated? How do you remove this control unit from the dash to check it? I made it through the cold without much warmth but I don't know if I can make it through the summer without cooling. Thanks for any advice.

[rexter3]

I would be looking for a vacumn leak myself.

[imidazol97]

Originally Posted by Debbie Mars

I have a 1997 Buick LaSabre and as of the last few months my heater will not blow very warm air. I have had the heater core flushed and I have replaced the thermostat. Still it doesn't blow warm air. Also the AC does not blow cold air. The compressor kicks in but the air does not get cold. Could it be the lever that slides back and forth from warm to cold not working. Is it electronic, mechanical, or vacuum activated? How do you remove this control unit from the dash to check it? I made it through the cold without much warmth but I don't know if I can make it through the summer without cooling. Thanks for any advice.

You have the standard AC unit with the lever that changes the amount of heat the way it sounds. The lever controls the heat through an electrical motor. That motor may not be working and moving the lever through the full range of motion.

First question would be if the air comes out of the right places when you set the buttons to heat, AC (front vents), to be sure the vacuum motors in the heater box are working right. If your vacuum is low due to cracked lines or storage tank or improper working of the control unit behind the glovebox area, that might cause the air to go the wrong way, but you still should get very hot heat out of those locations.

[HotZ28]

Originally Posted by imidazol97

You have the standard AC unit with the lever that changes the amount of heat the way it sounds. The lever controls the heat through an electrical motor. That motor may not be working and moving the lever through the full range of motion.

[Debbie Mars]

The air does come out in the correct spots. It just never gets very warm. I think Hot Z28 has it right. The lever is not changing the amount of heat coming through the system. My next question is where is the Air Mix Actuator located? I am going to try to check this out further this weekend. I will let you know what I find.

[imidazol97]

Originally Posted by Debbie Mars

The air does come out in the correct spots. It just never gets very warm. I think Hot Z28 has it right. The lever is not changing the amount of heat coming through the system. My next question is where is the Air Mix Actuator located? I am going to try to check this out further this weekend. I will let you know what I find.

You take off the plastic cover above the passenger's feet. It's a few small screws and taps. Remove the glovebox hinge from under the dash-about 5 screws there. Unclip lights and trunk button connection and oil reset power or just push off to side out of way.

The end of the heater core has the vacuum lines going into a vertical box that's screwed on with two screws. Above it on top of the heater core end of the AC heater box lying horizontally is the motor that moves a lever that changes the heat amount by changing the amount of air going through the heater core at the right end of the AC heater box.

The service manual says...

Temperature valve link adjustment:
1. Remove the temperature vale link rod from the emperature valve by snapping the rod out of the valve.
2. Start the vehicle. Make the following settings.
set the fan to position IIII high
set the temperature to full hot
3. Allow 45 seconds minimum for the A/C temperature valve actuator to move to the hot poistion
4. Move the temperature valve to the full hot position
5. snap the temperature valve link rod into the temperature valve.

So it sounds like you can unsnap the link rod out of the motor and can move it manually to see if it gives you full heat...

Then you can snap it into the motor and watch it move as you move the heat setting from full hot to full cold...

[HotZ28]

[imidazol97]

HotZ,

Is there a difference between the heater door control motor for the manual control system compared to the programmer controlled system for the automatic dual AC? It looks different in the manual I have.

[Luke.]

>Hot Z<
Impressive work with the pictures.

[Debbie Mars]

I did check out my car this past weekend and found that the actuator is not moving the door at all. I disconnected the rod that goes from the actuator to the door and the door closed allowing my heater to fully warm the air coming into my car. Now that I need the a/c instead of the heater I just propped the door open for now. However, is there a fuse that protects the circuit for the motor in the actuator? If so where is it located because the lever on the actuator is not moving at all when I slide the lever on the dashboard from cold to hot and visa versa. I am trying to determine wheter it might be a fuse, the motor itself, or one of the gears in the actuator. Thanks again for your help. By the way I bought a Chilton book but it does not tell you much about checking out any of this stuff.

[imidazol97]

Originally Posted by Debbie Mars

I did check out my car this past weekend and found that the actuator is not moving the door at all. I disconnected the rod that goes from the actuator to the door and the door closed allowing my heater to fully warm the air coming into my car. Now that I need the a/c instead of the heater I just propped the door open for now. However, is there a fuse that protects the circuit for the motor in the actuator? If so where is it located because the lever on the actuator is not moving at all when I slide the lever on the dashboard from cold to hot and visa versa. I am trying to determine wheter it might be a fuse, the motor itself, or one of the gears in the actuator. Thanks again for your help. By the way I bought a Chilton book but it does not tell you much about checking out any of this stuff.

The popular OTC manuals don't do a good enough job. The Helm manuals are what come from the factory authorized manuals when you order from the glovebox owner manual. Some are available on Amazon, Ebay, search the web.
helminc.com
http://www.helminc.com/helm/Result.a...689MT5DDM032KD

Note that Olds and Pontiac and Buick leSabre are all in the same book. I have the 98 version.