Need help with Temp. control sensor
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Need help with AC Temp. control sensor
Hay Guys
Can someone tell me where and how to change the driver side temp. control sensor for the AC? The car is a 97 coupe.
I have cool air on the passenger side and ambient air on the driver side.
Also, Climate Control is set at 65F. The Outside air is about 86.
Thanks
Can someone tell me where and how to change the driver side temp. control sensor for the AC? The car is a 97 coupe.
I have cool air on the passenger side and ambient air on the driver side.
Also, Climate Control is set at 65F. The Outside air is about 86.
Thanks
Last edited by bliehr; Jul 5, 2009 at 10:11 PM.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 28
From: Van Buren Arkansas
Wounded Warrior Escort '11
Well the sensor itself is directly adjacent to the ignition with the little black vented cover on it. About the only thing that could go wrong with it is the connector is off the rear of it or where the small cable goes to is disconnected. There is more likely a need to re-sync the HVAC system and I hear there is a method to command that but I truly don't have a clue what it is. Are you able to control any of the directional airflow? If not, I would first start checking on the small black vacuum tube that comes off the rear of the intake manifold at the MAP sensor and insure its still hooked up. Past that, make sure no battery acid has dripped onto it rendering it worthless where it enters the firewall.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Thanks for the reply.
Yes, I can direct the air flow from floor to defroster etc.
How is the small vented sensor panel held on? I hate to force plastic covers .
Any way to just get the air over to the driver side and bypass all this useless sensor junk?
Yes, I can direct the air flow from floor to defroster etc.
How is the small vented sensor panel held on? I hate to force plastic covers .
Any way to just get the air over to the driver side and bypass all this useless sensor junk?
AMP Racing
Joined: Aug 2006
Posts: 10,750
Likes: 587
From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
The cover comes off easily with a small screwdriver. I have had my off several times and it hasn't broken yet.
To pull out the sensor will require removing the radio surround. You might be able to see, with the help of a flashlight, if the sensor is damaged or the wire connection has come off. Otherwise, you will need to remove the radio surround.
To pull out the sensor will require removing the radio surround. You might be able to see, with the help of a flashlight, if the sensor is damaged or the wire connection has come off. Otherwise, you will need to remove the radio surround.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
I got to the driver side HVAC sensor and it looks ok, [as in not broken and the wires are connected.]
Anyone out there know how to re-sync the AC system.[If there is such a thing]
I did have the battery out of the car two times this past winter and the air worked fine on both sides last summer.
Anyone out there know how to re-sync the AC system.[If there is such a thing]
I did have the battery out of the car two times this past winter and the air worked fine on both sides last summer.
Melting Slicks
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
It's Fuse # 27.
From '02 Service Manual:
Re-Calibrating Actuators
Use the following steps to perform the calibration update:
Turn OFF the ignition.
Remove the battery positive voltage circuit fuse of the HVAC Control Module.
Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.
Wait 60 seconds.
Install the fuse.
From '02 Service Manual:
Re-Calibrating Actuators
Use the following steps to perform the calibration update:
Turn OFF the ignition.
Remove the battery positive voltage circuit fuse of the HVAC Control Module.
Important
The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.
Wait 60 seconds.
Install the fuse.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Thanks byronhunter, but no change in air on driver side.
Did get a BO338 H C code [ inside air temp sensor open] but that might be because I ran the car when testing with the sensor disconnected.
I think I'm lost again.
Thanks
Bob
Did get a BO338 H C code [ inside air temp sensor open] but that might be because I ran the car when testing with the sensor disconnected.
I think I'm lost again.
Thanks
Bob
Last edited by bliehr; Jul 10, 2009 at 04:37 PM.
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Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 28
From: Van Buren Arkansas
Wounded Warrior Escort '11
That code should have changed back to a history code only and not the current code once you reconnected it. I'm guessing you are going to have to open up the dash. There is a controller in there that is either having problems or its disconnected but I think you would see some codes if it was not hooked up.
Pro
Joined: Sep 2007
Posts: 735
Likes: 7
From: Bucks County Pa
Pass side cold, driver side warm.
Hello bliehr, you are looking at the wrong thing. There is no driver only side temp sensor, other than the control head and actuator sensors. If any of the three sensors,(outside air, inside air, and sun load), were bad the temps may not be quite right, but they would be consistent on both sides. In an auto ac car, when the condition exists that you have, the vast majority of times it is because of low refrigerant levels. Read the following,(see below) excerpt from another post and give it a try, if that doesn't work then you may have to either reindex the driver side actuator,( search for those posts), or replace it. Also when doing the fuse 27 pull procedure, the car should be off, ignition off, and sometimes it helps to wait a half hour, before putting fuse back in. When you put the fuse back in, listen closely under the dash, and you should hear the actuators going through their full range of motions for a moment, if you don't hear that, they are probably stuck or faulty. Also on the early vettes it sometimes helps to cancel out the codes before the fuse pull.
Good Luck
=================================
There were posts by plastifan about the proper charge levels that were excellant, and would put the system at optimum levels. In a nutshell you should strive for the following levels.
1, It is best to charge and check levels on the vette at 2000 rpm's, it can be done at 1000, or 1500 accurately, but you have to compensate for the lower rpms, with higher pressures. As the rpm's increase the low side will go lower, and the high side higher.
2, At 2000 rpm's with an 80% relative humidity, and ambient temp at 80 degrees, the low side should be 34psig, and the high side right around 250psig, this should yield at least 50 degrees or lower at the center duct with a thermometer.
If the temp is 90 degrees and the humidity is 80% the low side is 39psig, and the high around 310psig, this should yield 67 or lower at the center duct.
Humidity levels do make slight differences in the optimum read levels, as do temps. But if you get close to those numbers you will have an optimum system.
3, The proper way to make sure you have optimum levels is to evacuate the system, as you don't really know who worked on it before you, and might have let air or moisture, or even the wrong refrigerant in it. Then pull a vacumn of at least 29inches, for a few hours to dry it out, then recharge it being sure to add some proper oil. If it hasn't been disassembled, usually about 4 to 6 ounces of oil will be enough to protect the system. If you suspect a leak, which you should, because refrigerant doesn't wear out it leaks out, a bit of dye added will help you find it.
4, To answer your question about the difference in temps at the driver side duct when idling, this usually means that it is short of refrigerant. The refrigerant enters the evaporator on the passenger side duct and if there is not sufficient refrigerant in the system it does not circulate the entire evaporator before losing some of it's cold. If the difference in temps was happening at all engine speeds, that would usually be an actuator problem
Good Luck
=================================
There were posts by plastifan about the proper charge levels that were excellant, and would put the system at optimum levels. In a nutshell you should strive for the following levels.
1, It is best to charge and check levels on the vette at 2000 rpm's, it can be done at 1000, or 1500 accurately, but you have to compensate for the lower rpms, with higher pressures. As the rpm's increase the low side will go lower, and the high side higher.
2, At 2000 rpm's with an 80% relative humidity, and ambient temp at 80 degrees, the low side should be 34psig, and the high side right around 250psig, this should yield at least 50 degrees or lower at the center duct with a thermometer.
If the temp is 90 degrees and the humidity is 80% the low side is 39psig, and the high around 310psig, this should yield 67 or lower at the center duct.
Humidity levels do make slight differences in the optimum read levels, as do temps. But if you get close to those numbers you will have an optimum system.
3, The proper way to make sure you have optimum levels is to evacuate the system, as you don't really know who worked on it before you, and might have let air or moisture, or even the wrong refrigerant in it. Then pull a vacumn of at least 29inches, for a few hours to dry it out, then recharge it being sure to add some proper oil. If it hasn't been disassembled, usually about 4 to 6 ounces of oil will be enough to protect the system. If you suspect a leak, which you should, because refrigerant doesn't wear out it leaks out, a bit of dye added will help you find it.
4, To answer your question about the difference in temps at the driver side duct when idling, this usually means that it is short of refrigerant. The refrigerant enters the evaporator on the passenger side duct and if there is not sufficient refrigerant in the system it does not circulate the entire evaporator before losing some of it's cold. If the difference in temps was happening at all engine speeds, that would usually be an actuator problem
Last edited by bestvettever; Jul 11, 2009 at 12:53 AM.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Thanks very much bestvettever for the great info.
I'm still playing with it now and then. I'm going to try that fuse again and wait half hour. If that don't do it I'll go with the freon charge.
One other thing. When I switch to the front defroster, it feels like most of the air is coming out the right side of the defrost vent and a lot less on the driver side.
Does this have any meaning?
I'll let you guys know the outcome.
I'm still playing with it now and then. I'm going to try that fuse again and wait half hour. If that don't do it I'll go with the freon charge.
One other thing. When I switch to the front defroster, it feels like most of the air is coming out the right side of the defrost vent and a lot less on the driver side.
Does this have any meaning?
I'll let you guys know the outcome.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 103
Likes: 1
Well, turns out it was just low on 134A.
Checked both sides with gauges at 2000rpm, gave it a drink to bring the presser up, and I now have cold air.
Another question:
I went to purchase some refg. oil for the system and found it comes in about 4 different weights.
Which one do I need for this 97?
Thanks much to everyone for all the help.
What would I do without this forum and the people posting on it?
THANK YOU ALL
Checked both sides with gauges at 2000rpm, gave it a drink to bring the presser up, and I now have cold air.
Another question:
I went to purchase some refg. oil for the system and found it comes in about 4 different weights.
Which one do I need for this 97?
Thanks much to everyone for all the help.
What would I do without this forum and the people posting on it?
THANK YOU ALL
