2001 Corvette coupe. My hvac control is stuck on 69 degrees. I figured it was the ambient temp sensor and checked today. Pain to get to since I put the supercharger but I think i found the correct connection which did not have a sensor on it at all (perhaps I disconnected while working on installing the supercharger). Placed a new on today and still stuck on 69 degrees. Full disclosure, car is rarely driven, mostly to the track and some country road trips, so I disconnect the the battery ( kill lever) when not in use.
Any help or thoughts appreciated!

 

Once you install the new sensor it can take a little while for the system to read it.

 

Do you have a scan tool ??…if not see if you have any HVAC DTC’s particularly a B0333 stored using the DIC…being that the sensor was unplugged that DTC would set and the HVAC module will use a “substituted value” or default value to allow the HVAC to still operate…I believe 69 degrees is that value…if you have that DTC clear it and see if the ambient temperature sensor now reads correctly on the HVAC module…if this does not work and you have a DVOM we can do some voltage checks…BTW the temp reading will not update unless you drive more than 45 MPH for 1 minute…this sensor is a simple 2 wire thermistor using a 5 volt reference and a sensor ground wire.

 

Thank you both. Yes I have a scanner and will check and report back. Thank you for the information

 

Well if you have a scan tool look in Global OBD2…when you turn on your scan tool Global has the check engine light symbol…there you don’t have to enter the make, model etc…all of the data PIDS there can’t be “substituted” so what the PCM sees you will see…if it shows your ambient temp sensor see what temp it shows.

 

Here are codes:

B0333- outside air temp sensor open
B0361- left actuator feedback short to ground

Reset and ran at plus 60 mph for about 10 mins. Codes came right back. Perhaps the connection is poor. I’ll clean it and see.

 

Ok, so it can be a few things but I don't think it's a connection issue but look at it anyway...you may have a broken wire right at the connector itself...when you have the connector unplugged and with the key ON see if you see 5 volts on the light green/black wire using a clean spot of the frame for your ground...if you do connect the black lead of your DVOM to the gray/black wire...if the sensor ground is good you should again see 5 volts...if you don't see 5 volts on the light green/black wire the 5 volts comes from the HVAC module to a connector called C102...that connector is either a 20 pin round (early production) connector OR a 16 pin rectangular (late production) connector which reside near the right inner fender outboard of the battery...there are a few connectors there you'll see...you may have a broken 5 volt wire between C102 and the sensor itself...there may also be a broken 5 volt wire between the HVAC module and C102...you just have to do some digging...you may have a broken wire on sensor ground between C102 and a splice (S215)...S215 is a splice for 5 HVAC sensors so the sensor ground at the HVAC module is probably OK....as far as your new sensor if it is aftermarket or even OEM I'd check the resistance across it with an ohm meter…resistance values on next post along with C102 pin out…your trouble code says that the 5 volt reference is not being pulled to ground through the sensor…it is remaining above 4.90 volts…your new sensor may be bad if the DVOM reads “OL” !!

 

 

At least you picked a "nice" temperature.