Heat and A/C sensor above glovebox

[Danvers88]

Question from LCOC member #023780B.
My manual or auto heat setting has never worked right. I have the dash apart, and noticed a huge amount of white grease where the 2-wire plug goes into the back of the sensor attachment above the glove box.
The temp always starts out hot (with heat on) say set at 70, but after 10 minutes without me adjusting temp (on manual, not auto) you can hear the lever ducts move about every 9 - 15 seconds just a little at a time.
After a few minutes the air is coming out cool instead of about he temp I set., and the car has not reached the temp set.
Do you know any reason that white grease is crammed into the connection? Could the grease be preventing a good contact which is causing sensor disfuncion and my heat to cool down? After about 12 minutes I have to move it up to 90 to get any heat. It appears the sensor is working, one reason I think is because I disconnected the plug and now hot heat comes on at 65, and will not go cool unless I pop it down to 60.
Any help is appreciated. Please email me at: Danvers88@aol.com
Thanks, Bob

[pro-five-oh]

The grease is fine, its dielectric grease.

You need to do the diagnostic test before tearing apart the dash. You probably have a bad sensor, actuator, or head unit. But its hard to say without the test. See below.

http://www.lincolnsonline.com/tech/00007.html

[Danvers88]

I appreciate the quick reply, thank you, Bob

[pro-five-oh]

Bob,

From your PM to me: there isn't one sensor, there are 2 sensors (if I remember correctly). And there are also several actuators.

You can't replace parts one at a time here, you need to reassemble everything and run the climate control diagnostic to narrow down the problem. The instructions are in my first post.

Good luck. :)

[Nick]

From experience, I can tell you that if the upper sensor (I think it's a thermoresistor) connected to the ductwork with a small diameter, black tube is disconnected, it will cause constant temperature variation. The computer is cycling the climate control to try and find a temperature value to get into range. I'd follow what Pro said and get everything hooked up and do the self-test. It's the easiest way to diagnose the system.

[Danvers88]

You've helped alot thanks for the advice, Bob