Electronic Climate Control

[69Crazy]

I have a '90 Coupe with the electronic climate control that is out of control. The previous owner had the control module changed along with the heater damper actuator. Less than a year later, the problem has resurfaced. I don't want to throw cash at this.....any suggestions as to the root cause of the problem?

 

[Rob]

Can you be more specific about what the problem is? Have you checked for trouble codes?

 

[69Crazy]

I am waiting for the service manual I ordered, to know how to proceed. Currently I get no warm air in the heat or defrost mode. Also, the action of the A/C system when set to Auto can be erratic. It seems to cool only in the recirculate mode. The lights above the buttons blink when pushed (indicating a problem detected....according to the owner's manual). I was wondering if there might be a known common problem....a short maybe. There was a recall about the wiring harness shorting on the hood release cable. There was a service bulletin about the electronic control failure. I ordered the service bulletin reprint about three weeks ago and have not seen it yet. Maybe it will shed some light on the cause. I am a new to C-4 owner and I guess that extraction of computer error codes will become something I have to be familiar with....what happened to the good old days????

Louie

 

[Rob]

LOL, the good old days of grabbing a wrench, screwdriver and adjusting points are looooooooooooong gone. :L I have a '90 service manual here. Let me see what I can dig up. I may not be able to get back to you till tomorrow though.

 

[Rob]

From 1C1-2 of the '90 Service Manual

Diagnosis
If a system fault is detected, the LED of the operating mode the system is in at the time of fault detection will falsh at a rate of 60 times per minute. Fault codes will then be stored.
To enter the diangostic mode, push and hold the fan up arros and fan down arrow at the same time for approximately 5 seconds. The LDC (Liquid Crystal Display) will show "-00." Push "AUTO" and the LCD will show any fault codes stored in the programmer.

<B>Fault Codes</b>
<b>Description</b>

00
NOT USED

01
TEMP. DOOR MOTOR CIRCUIT FAILURE

02
TEMP. DOOR MOTOR CIRCUIT FAILURE

03
AMBIENT SENSOR OPEN

04
AMBIENT SENSOR SHORT

05
IN-CAR TEMP. SENSOR OPEN

06
IN-CAR TEMP. SENSOR SHORT

07
SOLAR LOAD SENSOR OPEN

08
SOLAR LOAD SENSOR SHORT

09
LOW FREON DETECTED

10
UART FAILURE

While in the diagnostic mode, it is possible to check several different system parameters (circuits or systems). This is done by pressing the fan "up" or fan "down" button. Once the parameter to be checked has been chosen, the fan "AUTO" button is pressed and a diagnostic value is displayed on the LDC. A list of system parameters and their normal operating ranges can be found [on the next page].

For further diagnosis of ECC system codes, refer to the diagnostic charts in this section. To exit diagnostics, change to a different ECC system mode.

 

[69Crazy]

Thanks for the information

Rob,
Thanks for your time and effort. I am heading out to the garage (big hammer in hand) to "diagnose" the problem. My evolution as a mechanic stopped in about 1971. That is why "my" Corvette is a '69. But, my wife decided that this is "her Corvette", so I guess I will have to grow a little.

Louie

 

[Rob]

LOL, let us know what you find.

-Rob

 

[69Crazy]

Diagnostic overload

When I was a young pup, the most important diagnostic tool was a piece of garden hose. This "stethoscope" was invaluable in determining where that "strange noise" was coming from....except for my friend that once got his caught in the fanbelt of a running engine...but; I digress. Now, at the age of 48 I have more diagnostic codes than liver spots on my skin.

In the general mode I got the code 01 for Temp Door motor circuit failure

But when keying through the other diagnostics, I recorded 21 error codes in the 25 different parameters tested. I tried the diagnostic in every climate control mode and received more error codes. Sometimes the same as the off position, sometimes different. So, I received the following error codes:
73,147,107,127,120,31,32,33,151,55,56,128,123,147,132,15,60,02,75,79....
and on and on. With 25 parameters tested in 7 operating modes I got a lifetime supply of error codes

Parameter five yielded the tidal wave of codes giving me (in the various climate control modes) 100,101,103,104,105,106,107,109,110, & 120

So, I am off to the dealership to see if I can con them into letting me copy the page out of the service manual that deals with these codes. Or maybe I should just consider the whole thing FUBAR....Wait, better yet, my wife(in a short skirt:booty) will be able to get all of the information that I need....Going to send Mata Hari behind the enemy lines once again.....Never send a man to do a woman's job.

Louie :confused

 

[69Crazy]

Now that I think about it

I am wondering why I didn't get the code 666.....'cuz I think this computer is posessed!

Louie