92 Vette A/c Inop
07-01-2007, 01:41 PM
#1
3rd Gear
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92 Vette A/c Inop
Well im chasing this crazy problem and just wondering if ne1 can help me.
1992 Vette A/c Comp Wont Kick On.. What ive done
Had the system filled with fresh r12. Cleared all the codes out of the programmer. I can command the compressor on with a Tech 1. The A/c programmer is receiving power from the control head when i test it with a test lamp. if i jump the a/c relay the compressor kicks on. i belive the PCM grounds that relay so i took a known good PCM out of a friends car and hooked that up. Nothing worked. Ive also replaced all 3 (programmer,Pcm,control head) just to see. All my pressure switches have been replaced and i cannot see any frayed wires under the dash or anywhere..All terminals at all connectors seem tight. If anyone has any ideas that would be great. I need my a/c thanks guys
1992 Vette A/c Comp Wont Kick On.. What ive done
Had the system filled with fresh r12. Cleared all the codes out of the programmer. I can command the compressor on with a Tech 1. The A/c programmer is receiving power from the control head when i test it with a test lamp. if i jump the a/c relay the compressor kicks on. i belive the PCM grounds that relay so i took a known good PCM out of a friends car and hooked that up. Nothing worked. Ive also replaced all 3 (programmer,Pcm,control head) just to see. All my pressure switches have been replaced and i cannot see any frayed wires under the dash or anywhere..All terminals at all connectors seem tight. If anyone has any ideas that would be great. I need my a/c thanks guys
07-01-2007, 02:27 PM
#2
Le Mans Master
Usually a bad connection/intermittent open at the Low Pressure Switch. However, the fact you can use the CCM link (you are using that aren't you?) and make it work points to a bad Control Panel. Controls send the a/c request over serial data lines to the Programmer which then relays it to the PCM. PCM drives the Relay as long as the Low Pressure Switch contacts are closed. Since you can send the "on" signal from your Scanner to the Programmer and it works, your control panel doesn't seem to be. Anything else out? Display?
07-01-2007, 02:39 PM
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3rd Gear
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the control head seems to be working perfectly fine. when i command the. temp down to 60 for the ac. to kick on and i hook my test light up the programmer i can toggle the test light on and off while turing the control head on and off. i used a control head off of a 93 dont know if its compatable but everything else worked but the a/c. i figured the control head to. Ill check the connections. thank you for your input
07-01-2007, 11:19 PM
#4
Le Mans Master
Try www.acdelco.com and if it's still a stocking number, x-reference to other Years.
Don't know if your on/off is a valid test. If you've got the Shop Manual (I don't have access to your Year) there's usually a couple steps to follow with the Tech 1. First, use the CCM link to send the Control Panel signal for an a/c request. If that doesn't crank it on, bypass the Programmer (CCM link) and direct the PCM to ground the relay. If it works, the PCM, Relay and sensors (Low and Pressure Sensors are good). If it doesn't, replace the Programmer.
Don't know if your on/off is a valid test. If you've got the Shop Manual (I don't have access to your Year) there's usually a couple steps to follow with the Tech 1. First, use the CCM link to send the Control Panel signal for an a/c request. If that doesn't crank it on, bypass the Programmer (CCM link) and direct the PCM to ground the relay. If it works, the PCM, Relay and sensors (Low and Pressure Sensors are good). If it doesn't, replace the Programmer.
