Eternal Temperature Incorrect, causing A/C to not function

[2004LSflip]

Lately my external temperature has been incorrect. It usually displays approximately 16 degrees, but varies a lot regardless of actual temperature. It can go down to the negatives but rarely goes above 30 (Actual temperature is in the 80s here).

This is causing my A/C to not work. I know this because occasionally it will go up and display the actual temperature. It goes up slowly, one degree at a time and after it hits 60-65 or so the A/C will start to work but it will inevitably drop back down and once it hits 65-60 the AC will stop blowing cold. Sometimes it just goes up to the 50s and starts dropping back down again.

I have tried replacing the external temperature sensor (on the bumper) but that didn't make a difference. What should I check next?

 

[joegr]

I think you have misidentified the cause of your problem. An incorrect exterior temperature reading is no causing your AC to not work. Instead, a fault in you DATC is causing your exterior temperature display to be wrong and your AC to not work. Possibly a reference voltage problem.

Did you try a DATC self diagnostic?

 

[2004LSflip]

I think you have misidentified the cause of your problem. An incorrect exterior temperature reading is no causing your AC to not work. Instead, a fault in you DATC is causing your exterior temperature display to be wrong and your AC to not work. Possibly a reference voltage problem.

Did you try a DATC self diagnostic?

That makes sense, however it does kick on/off at that certain point around 65 degrees. This is very consistent. But it definitely could be (is?) a fault with the DATC. How do I diagnose that?
EDIT: Nevermind I found that in the manual. Will I be able to use a regular engine scanner?

 

[joegr]

That makes sense, however it does kick on/off at that certain point around 65 degrees. This is very consistent. But it definitely could be (is?) a fault with the DATC. How do I diagnose that?
EDIT: Nevermind I found that in the manual. Will I be able to use a regular engine scanner?

No, it has to be Ford specific to pick up codes from the climate control. Alternately, you can run the front panel self test and the climate control codes will display on the DATC itself.

Assuming from your name that you have a 2nd gen (since you didn't say), here is how:
http://deneau.info/ls/s6x~us~en~file=s6xc0003.htm~gen~ref.htm

 

[2004LSflip]

Ok I ran the front panel test and no codes were displayed. The entire panel would just light up, so this means no faults were detected.

 

[2004LSflip]

I should read more before posting. I assume this means i should replace to DATC module?

 

[joegr]

I should read more before posting. I assume this means i should replace to DATC module?

Well, it's not detecting any faults, but I do still suspect that replacement of the DATC is the solution.
You could verify the wiring between the exterior temperature sensor and the DATC to be sure that problem is in the DATC.

 

[2004LSflip]

Well, it's not detecting any faults, but I do still suspect that replacement of the DATC is the solution.
You could verify the wiring between the exterior temperature sensor and the DATC to be sure that problem is in the DATC.

Ah ok Ill try that soon. Thank you very much for your help!