AC / Climate Control
Pro
Joined: Apr 2008
Posts: 586
Likes: 119
From: Saint Cloud, FL
Sorry you didn't seem very thrilled with AllData, but it along with FSM does seem to point to the Programmer you mentioned.
I have a parts list for the C4 and oddly enough it doesn't list a part for the '94 model year A/C Programmer. That I don't understand.
At any rate go to www.gmpartsdirect.com/catalog/frameset.cfm and search for "prog" for the 94 vette. They have parts listed there for our year model. They're about $100. I would contact them before ordering just to make sure you get the correct part.
I have a parts list for the C4 and oddly enough it doesn't list a part for the '94 model year A/C Programmer. That I don't understand.
At any rate go to www.gmpartsdirect.com/catalog/frameset.cfm and search for "prog" for the 94 vette. They have parts listed there for our year model. They're about $100. I would contact them before ordering just to make sure you get the correct part.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
But, the procedure that I described below with the Tech-1A scan-tool does indeed work every time and eliminate guessing.
I've used it many times.
What I have found is many people don't understand this method even after it is explained, or find that jumpering the two serial-buses together is too intimidating or too much of a bother.
With this procedure, you can send the same commands to the programmer with the Tech-1A and see if the programmer responds correctly -- this takes the control head completely out of the picture.
If the programmer responds correctly, the problem isn't the programmer.
If the programmer doesn't respond correctly, then the problem is the programmer. It's actually very simple.
You can also send commands to the programmer with the control head and monitor those commands on the serial-bus with the Tech-1A. If you send a command with the control head and it is visible on the Tech-1A in plain English, then the control head is working -- once again, very simple.
There is a way to trouble-shoot the problem with the C68 climate control.
It requires a Vetronix Tech-1A scan-tool (the same tool GM dealers used for years) and some jumpering of wires -- this is all in the FSM.
There are two serial buses:
1) Serial bus for the radio control to communicate with the receiver.
2) Serial bus for the C68 climate control head to communicate with the programmer.
By jumpering these two buses together, the Tech-1A scan-tool can access the C68 bus on the ALDL connector.
Once these buses are jumpered, you can use the Tech-1A with the "body" cartridge to diagnose the problems with the C68 climate control.
Things you can do once the Tech-1A is able to access the bus:
1) You can simulate the control head with the Tech-1A and send commands to the programmer to see if it responds.
2) You can monitor the commands (in plain English) from the control head to the programmer to see if the control head is functioning correctly.
This eliminates guessing.
After diagnosis, you are supposed to remove the jumper on the buses.
What I did was run the jumper through a small switch so I could easily connect the buses and diagnose the system and then disconnect it easily.
Tom Piper
It requires a Vetronix Tech-1A scan-tool (the same tool GM dealers used for years) and some jumpering of wires -- this is all in the FSM.
There are two serial buses:
1) Serial bus for the radio control to communicate with the receiver.
2) Serial bus for the C68 climate control head to communicate with the programmer.
By jumpering these two buses together, the Tech-1A scan-tool can access the C68 bus on the ALDL connector.
Once these buses are jumpered, you can use the Tech-1A with the "body" cartridge to diagnose the problems with the C68 climate control.
Things you can do once the Tech-1A is able to access the bus:
1) You can simulate the control head with the Tech-1A and send commands to the programmer to see if it responds.
2) You can monitor the commands (in plain English) from the control head to the programmer to see if the control head is functioning correctly.
This eliminates guessing.
After diagnosis, you are supposed to remove the jumper on the buses.
What I did was run the jumper through a small switch so I could easily connect the buses and diagnose the system and then disconnect it easily.
Tom Piper
Last edited by Tom Piper; Oct 23, 2008 at 07:10 AM.
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 43
Likes: 0
From: Cypress Texas
Part arrived
Programmer showed up and I am going to perform the transplant tonight. You have all been very helpful. Thanks a million.
BTW, anything you would caution me about for this before opening things back up?
BTW, anything you would caution me about for this before opening things back up?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Usual stuff - disconnect the battery. Be careful when you remove the vacuum harness from the Programmer. When you start it back up, there will be a brief delay while the Temp Door motor is cycled from fully open to fully closed and nothing is going to work while that is taking place. Give it a couple of minutes and then everything should respond.
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Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Press fan up and fan down at the same time and hold until the display reads 00 when it does press the center button between the up and down if this changes the display to something other than 00 that is the trouble code for whatever is wrong. If the inside temp sensor is reading way hot and programmed temp is lower it will run the ac as well there a bucnch of codes that can be tretrieved as well that tell yiu what each sensor in the system is doing...
Burning Brakes
Joined: Jun 2000
Posts: 913
Likes: 17
From: Chatsworth, Ga.
A/C Programmer
PARTS
Qty Description Brand Sku Price Total
Vehicle:1992, CHEVROLET, CORVETTE, V8-350ci 5.7L F/I Vi
1 Heater Parts
a/c Auto Elec Cont (c68) ; Corvette; Years:1992-1992; Per Car Qty:1; ACDELCO US 15-73394 $175.65 $175.65
autopartsgiant.com
As far as I remember this is the A/C Heater Programmer Module. They are specific to year.
I replaced my months ago and this place is the only one who had them for a decent price.
The problem with them is cold solder joins on a board inside.
I will send the procedure to fix it in a PM.
Qty Description Brand Sku Price Total
Vehicle:1992, CHEVROLET, CORVETTE, V8-350ci 5.7L F/I Vi
1 Heater Parts
a/c Auto Elec Cont (c68) ; Corvette; Years:1992-1992; Per Car Qty:1; ACDELCO US 15-73394 $175.65 $175.65
autopartsgiant.com
As far as I remember this is the A/C Heater Programmer Module. They are specific to year.
I replaced my months ago and this place is the only one who had them for a decent price.
The problem with them is cold solder joins on a board inside.
I will send the procedure to fix it in a PM.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Use the previous poster's instructions to determine the error code(s).
Also there is a reset procedure and you can always disconnect the battery (when key is NOT in the ignition) to reset it too.
Regarding the outside temp being wrong, likely the temp sensor is mounted below and in front of the AC condensor (radiator) and perhaps has been damaged or the wire connector to it is dirty.
Also remember it will show last temp for a few minutes until it it is sure it can display correct new temps.
Burning Brakes
Joined: Apr 2007
Posts: 1,178
Likes: 15
From: Montreal Quebec
Press fan up and fan down at the same time and hold until the display reads 00 when it does press the center button between the up and down if this changes the display to something other than 00 that is the trouble code for whatever is wrong. If the inside temp sensor is reading way hot and programmed temp is lower it will run the ac as well there a bucnch of codes that can be tretrieved as well that tell yiu what each sensor in the system is doing...
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
if you unplug the sensor the wires that it plugs into should have 5 volts across them and if with the sensor plugged in and covered to not see any sun at all go to parameter 04 instead of 00 and read that it should be 225 or close to it. The programmer i bet thinks you are in the balzing sun and need more ac....
Burning Brakes
Joined: Apr 2007
Posts: 1,178
Likes: 15
From: Montreal Quebec
my solar load sensor on the dash dosen't have the little plastic cap on it... should i just cover it and reset to try and is that might be the only cause??? but yesterday i take it out for a ride and it was +/- 85 outside and the outside temp indicate 68 at start up and was slowly going down to 46 by the time i was back 
where is the sensor for outside temp located at (i think in the front around the middle of the car is that right???)
where is the sensor for outside temp located at (i think in the front around the middle of the car is that right???)
