2000 Ford Windstar A/C won't turn on

Tiny
FRYEMAN
  • MEMBER
  • 2000 FORD WINDSTAR
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 104,000 MILES
Good Morning, My A/C compressor on my van won't turn on. They tell me the freon is full, that the PCM turns on the compressor in "test mode". Both places I have taken it to are continuing to look for the outside air temp sensor. They get a B1254 code (air temp ext snsr failure). No one can seem to find the sensor. My questions: 1) I don't have an indication of outside air temp inside the vehicle. So would I actually have an external air sensor? It's supposed to be located behind the front bumper and no one can seem to find it. 2) If the IAT was bad would that cause the A/C not to turn on due to the sensor showing a cold temp? And isn't the IAT part of the MAF sensor?

Thanks, Rodney
Do you
have the same problem?
Yes
No
Tuesday, July 7th, 2009 AT 8:47 AM

7 Replies

Tiny
MERLIN2021
  • EXPERT


http://www.2carpros.com/forum/automotive_pictures/62217_AAT_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Windstar_2.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_windstar38_1.jpg


Top is 3.0 Bottom is 3.8 Iat= Intake air temp, not the same as AAT= ambient air temp! 3.0(top) it is at #22, Bottom(3.8) it's at #25
IAT= Intake air temp
AAT= ambient air temp, not the same! AAT is what your looking for!
Was this
answer
helpful?
Yes
No
+1
Tuesday, July 7th, 2009 AT 8:58 AM
Tiny
FRYEMAN
  • MEMBER
I have all of that. But is the AAT the sensor that can keep the A/C from coming on? Or is it the IAT sensor? And, do all vehicles have this AAT or is it possible that it really doesn't exist? The vehicle hasn't been in a wreck so no one has forgot to put the AAT back on. The A/C worked at the end of the season last fall (November 08) but now won't turn on. The 2 A/C repair places seem to be chasing their tails on this and have now had the vehicle for 2 weeks total and can find nothing. My question is which air temp sensor, (AAT, IAT) controls the A/C? Or what else could possibly be causing this lack of A/C?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 9:09 AM
Tiny
MERLIN2021
  • EXPERT
Yours has it, and the IAT will not prevent the a/c from working, have them bypass the low pressure cutout switch as a test, does the compressor run?
A defective AAT that is showing a code can give these symtoms.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 9:21 AM
Tiny
FRYEMAN
  • MEMBER
So the low pressure cutout switch is in parallel with the AAT? Jumpering out one will effectively get both out of the circuit?

The code (B1254) will not come up unless it is real is that what you are saying?

If all of this is true then where in the world could the AAT physically be located? They even took off the fron bumper and said they couldn't find anything. Two places said this. Any ideas?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 9:36 AM
Tiny
MERLIN2021
  • EXPERT
Usually located near top or bottom in front of the radiator. It would help if I knew which engine you have 3.0 or 3.8?


http://www.2carpros.com/forum/automotive_pictures/62217_AAT_2.jpg

Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 10:43 AM
Tiny
FRYEMAN
  • MEMBER
I have the 3.8l engine.

What about jumpering out the low pressure cut out switch? Will that jumper out both the AAT and low pressure switch?
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 11:49 AM
Tiny
MERLIN2021
  • EXPERT
It might, but it's only to test for the switch actually causing your problem, I havnt seen the AAT cause it.
Was this
answer
helpful?
Yes
No
Tuesday, July 7th, 2009 AT 2:35 PM

Please login or register to post a reply.

Recommended Guides