Another Climate Control Mystery

[Reverie]

For the last year my climate control panel has indicated an outside air temperature of 50F. I performed all of the usual steps and got these results:

1. Checked all the connections and plugs. No change
2. Removed the Outside Air Temperature Sensor: No change.
3. Jumpered the connection where the Air Temperature Sensor Usually Mounts: No change.
4. Installed new Temperature Sensor: Still reads 50 but will occasionally start ticking down to -18F then slowly returns to 50.
5. Reinstalled Original Temperature Sensor: Back to a reading of 50F.
6. Had the A/C Serviced: No change in the reading.
7. Took it To the Ford Dealership: After the indifferent questions, the technician spent ten minutes looking at the truck and told me it was the outside air temperature sensor. He then tried to convince me my customer installed XM Radio antenna was the sensor. That is a $110 I will never get back.
8. Replaced the Control Panel: No Change. Want to buy a perfectly good control panel? Cheap?

BONUS SYMPTOM: Like most of the country, we are experiencing some very hot temperatures right now. Occasionally, when the temperature exceeds 95F, the indicated outside temperature will start ticking upward until it accurately reads the outside temperature. Then the inside temperature works as designed and life is grand. Until the truck is shut off or the temperature outside falls below about 95F.

Every so-called expert has looked at this, given me long and drawn out explanations but nobody can identify the problem. I have traced the wire as far as I can looking for intermittant open but without an accurate wiring diagram I can't get back to the panel where I ASSUME the temperature info is mixed with the cabin temperature to schedule the air conditioned air.

Has anyone seen this and has anyone got a solution? It is driving me crazy.

Reverie a/k/a "Melting in Atlanta"

[airjeff]

Try to track down a wiring schematic and/or just figure out where the wires go. I think it's a good idea to verify there isn't a wiring problem. If I had to guess, the ECM(or whatever Ford calls it) is having a problem. I'm pretty sure the control panel is just displays and buttons, the actual control of the system is done by the ECM. Know anyone that would let you borrow their ECM to test?

[BucOff]

You could try contacting Sargar on the ORG. He is a member of the Georgia Powerstroke Diesel Association located in the Georgia section. He has a shop in the Loganville area and may be able to help. Not sure of his costs for diagnostics, but I would fully trust his abilities first and above any dealer in town.