Hello all. My Heater ac (electronic climate control) is giving me fits. I have an 89 with the digital temp control. The digital reading that says outside temp reads 49 degrees ALL the time no matter if its 102 degrees outside or -10 degrees. The hot / cold electric actuator door doesn't open or close so it can't open/shut the door to change the temp in the vehicle. I do however know the actuator is a good one because I tried it on another car with working heat / ac. I replaced the inside temp sensor to no avail. Does anyone have any ideas? Thanks, Bobbo

 

Did You Remove the control unit to another car?? The control unit will list codes I believe 1-9..You might check your programmer which is on the left side under the dash..Also there are two sensors for temp an inside and an outside..

 

Outside Temp Sensor is a thermistor (resistance decreases as it warms up) mounted on the radiator. Disconnect the harness and the display should indicate -38 degrees. Ground the black wire and you should see something in excess of 100. Check the Light Green wire for the reference voltage - it should be 5 volts.

Temp door is controlled by an electric motor mounted on the right side of the heater box. I don't know how you could make it work in another vehicle unless it was GM electronic air. You can observe the door it controls by removing the Blower Module on the Evaporater Case - right side of the Firewall - and looking inside. If it isn't moving between 60 and 90 check the linkage by removing the passenger side hush panel and ECM.

Trouble Codes are indicated by a Flashing LED at the Exterior Temp Display. Access by holding the Ext Temp Button and Pressing and Releasing the Auto Button. A Mode Number will pop up. Advance it to 08 by pressing the Warm Button, then press Cool for the Codes: 00 No Faults; 01 Temp Door Motor Feedback Open; 02 Outside Temp Sensor open; 04 Outside Temp Sensor shorted; 08 Inside Temp Sensor open; 16 Inside Temp Sensor shorted.

 

Thanks Happy Dad. The only thing I was able to try swapping on the other vette was the actuator because my friend let it go. How do I check the control unit codes and where is the outside temp switch? I hate to ask so many questions but I'm new to the vette heating system. I do know where the programmer is located. Thank you.