Lordkay972
I'm Awesome
First off, I'm not sure if there's a post on this already but I didn't see one pinned so I apologize if this is a repost.
I have a '92 Silverado1500 with a 350 in it. I bought it in the winter last year so I wasn't too worried about the A/C, but as it started getting hotter I made it a priority to fix the problem. I figured "Hey, I'll take a few minutes, charge the system and it'll be good to go." WRONG! Long story short, the A/C wouldn't work because of a faulty low pressure sensor. This sensor is supposed to warn the driver that he/she needs to charge the system. After changing it out three times I got on Google and found the fix. So after you read that semi-pointless story, if you can relate to my problem, then this might help you out.
BULLETIN NUMBER: 93-1B-109
SECTION: 1B Air Conditioning
NUMBER: 13
CORPORATE REFERENCE NUMBER: 261201R
DATE: August 1993
SUBJECT:
A/C LOW CHARGE INDICATOR FLASHES
(DISCONNECT LOW CHARGE DETECTION FEATURE)
MODELS:
1991-93 C/K AND TOPKICK/KODIAK WITH AIR CONDITIONING
THIS BULLETIN IS BEING REVISED TO INCLUDE THE 1993 MODEL YEAR AND THE TOPKICK/KODIAK MODELS.
Some owners of 1991-93 C/K and Topkick/Kodiak vehicles may comment that the A/C letters in the middle of the control head face are flashing. The HVAC control system used on the above subject vehicles incorporates a low A/C charge warning system. If a low charge is detected. the control head will not allow the compressor to engage and the A/C letters in the middle of the control head face that usually signify A/C operation will blink.
The HVAC control head determines a low charge by monitoring the circuit from the pressure cycling switch. If the cycling switch will not allow the compressor to run more than 1.5 seconds. ten times in a row. the control head assumes a low charge and disables the compressor until reset.
On some vehicles, it has been found that the wire from the pressure cycling switch to the control head is sensitive to EMI (electro magnetic interference) and gives false compressor cycling information to the HVAC control head which then disables the compressor.
If you encounter a vehicle with the control head A/C indicator flashing the low charge signal but can find no reason for the flash using normal diagnostic procedures, including checking the wiring harness for chafing. remove the pressure cycling switch feedback wire from the control head connector. This process disables the A/C Low Charge detection feature, however. the customer will still be alerted to a low charge by excessive compressor cycling and poor A/C performance.
SERVICE PROCEDURE
1.Remove the instrument panel trim bezel.
2.Remove the A/C control head.
3.Disconnect the control head electrical connector.
4.C/K Models:
Remove the dark green circuit 59 wire located in harness connector socket number one. Do not cut the wire, remove the terminal (Refer to the C/K Electrical Diagrams and Diagnosis Manual, under the air conditioning section).
Edit: (if you do not know what wire this is talking about, it's the dark green one on the bottom right of the connector. You might have to use some force to remove the pin from the connector.)
Topkick/Kodiak:
Remove the dark blue circuit 248 wire located in harness connector # XXXXX socket number one. Do not cut the wire, remove the terminal and tape (Refer to Topkick/Kodiak Electrical Diagrams and Diagnosis Manual. under the air conditioning section).
5.Fold the wire back along the harness and tape it so that it cannot short when the control head is installed.
6.Install the control head.
7.Install the instrument panel bezel.
After this, my truck is freezing cold. Hope it helps someone else.
Sent from my HTC One using Tapatalk
I have a '92 Silverado1500 with a 350 in it. I bought it in the winter last year so I wasn't too worried about the A/C, but as it started getting hotter I made it a priority to fix the problem. I figured "Hey, I'll take a few minutes, charge the system and it'll be good to go." WRONG! Long story short, the A/C wouldn't work because of a faulty low pressure sensor. This sensor is supposed to warn the driver that he/she needs to charge the system. After changing it out three times I got on Google and found the fix. So after you read that semi-pointless story, if you can relate to my problem, then this might help you out.
BULLETIN NUMBER: 93-1B-109
SECTION: 1B Air Conditioning
NUMBER: 13
CORPORATE REFERENCE NUMBER: 261201R
DATE: August 1993
SUBJECT:
A/C LOW CHARGE INDICATOR FLASHES
(DISCONNECT LOW CHARGE DETECTION FEATURE)
MODELS:
1991-93 C/K AND TOPKICK/KODIAK WITH AIR CONDITIONING
THIS BULLETIN IS BEING REVISED TO INCLUDE THE 1993 MODEL YEAR AND THE TOPKICK/KODIAK MODELS.
Some owners of 1991-93 C/K and Topkick/Kodiak vehicles may comment that the A/C letters in the middle of the control head face are flashing. The HVAC control system used on the above subject vehicles incorporates a low A/C charge warning system. If a low charge is detected. the control head will not allow the compressor to engage and the A/C letters in the middle of the control head face that usually signify A/C operation will blink.
The HVAC control head determines a low charge by monitoring the circuit from the pressure cycling switch. If the cycling switch will not allow the compressor to run more than 1.5 seconds. ten times in a row. the control head assumes a low charge and disables the compressor until reset.
On some vehicles, it has been found that the wire from the pressure cycling switch to the control head is sensitive to EMI (electro magnetic interference) and gives false compressor cycling information to the HVAC control head which then disables the compressor.
If you encounter a vehicle with the control head A/C indicator flashing the low charge signal but can find no reason for the flash using normal diagnostic procedures, including checking the wiring harness for chafing. remove the pressure cycling switch feedback wire from the control head connector. This process disables the A/C Low Charge detection feature, however. the customer will still be alerted to a low charge by excessive compressor cycling and poor A/C performance.
SERVICE PROCEDURE
1.Remove the instrument panel trim bezel.
2.Remove the A/C control head.
3.Disconnect the control head electrical connector.
4.C/K Models:
Remove the dark green circuit 59 wire located in harness connector socket number one. Do not cut the wire, remove the terminal (Refer to the C/K Electrical Diagrams and Diagnosis Manual, under the air conditioning section).
Edit: (if you do not know what wire this is talking about, it's the dark green one on the bottom right of the connector. You might have to use some force to remove the pin from the connector.)
Topkick/Kodiak:
Remove the dark blue circuit 248 wire located in harness connector # XXXXX socket number one. Do not cut the wire, remove the terminal and tape (Refer to Topkick/Kodiak Electrical Diagrams and Diagnosis Manual. under the air conditioning section).
5.Fold the wire back along the harness and tape it so that it cannot short when the control head is installed.
6.Install the control head.
7.Install the instrument panel bezel.
After this, my truck is freezing cold. Hope it helps someone else.
Sent from my HTC One using Tapatalk
Sometimes that feature worked exactly like it was supposed to - detected too-frequent compressor cycling, and shut down the A/C.
