The ambient air temp. reading on my climate control panel no longer seems to be working. It reads 49* all the time & always worked until recently.

I searched the forum and found these threads;

http://forums.corvetteforum.com/c4-g...eads-50-a.html

http://forums.corvetteforum.com/c4-t...mp-sensor.html


It says to replace the lazy sensor w/ GM part #16047526 which cross references to AC Delco part #ACD15-71458. I got the part and it seems to have a two prong wire & plug lead that is to short to mount the new sensor in my '89 C4?

I know GM used this ambient temp. sensor in many different models from the late 80's to early 90's but the wire leads for this part will not pass thru the grommeted plastic bulkhead and plug into the male two prong weatherpack connector found in the engine compartment under the OEM airbox.

Anyone replace this sensor in an '89... where did you get the part?
Do I need a Corvette specific part??

What about GM part #16123341, ambient sensor listed for '89~'96 Chevy's??

 

Nobody's replaced an ambient air temperature sensor that appears to be frozen?

Someone.......anyone????????????????

 

Nope - never seen one go bad unless it's been crushed in an accident, but there is another thread going about one on a later Year which has much better diagnostics and communication over serial data lines with a Body Module that the '89 lacks. Also, if I remember right, there's a bulkhead connector so you don't have to pull anything through the Firewall.

For '89, there are 2 trouble codes for a bad Sensor - open Circuit which should read -38 degrees on the Controls and a grounded Circuit which would be in the 100's. Yours is doing neither leading me to believe there's a possibility of a Control Panel problem and maybe there's nothing wrong with the Sensor. You might want to see what the Sensor Resistance is first, say ohm it out early in the morning and then during the heat of the day and if that value has decreased, it just may be working (published values are 4400 ohms at 60 degrees; 2200 ohms at 85). It is a Thermistor meaning it's resistance will drop as it heats up).

The Sensor itself is mounted on the Radiator Shroud down low by the Condenser. You mentioned the air intake and if you mean the TPI Plenum, that's the Air Intake Temp Sensor used by the ECM. The '89's a/c only communicates with the ECM for idle and WOT control - otherwise it's out of the picture.

For limited Diagnostics and Trouble Codes there will be flashing LCD below the readout when you turn on the ignition. To see if there's anything going on, press the Ext Temp and Auto Buttons at the same time. Press the Warm until you see 08 and then Cool for any Codes. 00 means there aren't any. 02 is an Open Sensor; 04 is shorted.

You could also try clearing memory by disconnecting and reconnecting the battery. After you do that, nothing is going to work for a few minutes as the Processor (Control Panel) is going to cycle the
Temp Door to determine it's position electronically and it may even show a -38 degrees while it's making the calculation. Once done, the Compressor should engage, the Blower should blow and maybe the Display will go to something reasonably resembling the outside air temp. Finally, simply disconnecting the Sensor should spit out the -38 which you can clear by pulling the Ctsy/clk Fuse or just let it run for 3 minutes after you hook it back up. The key here is to figure out if it's a Sensor or something else.