May be the ground problem that others have had (including myself). I did my own ground mod and did NOT buy any parts, but used wire and connectors I already had.
REFER TO Technical Service Bulletin ........
08-9-1
EATC BLOWER INTERMITTENTLY INOPERATIVE - STUCK ON HIGH/OFF
Publication Date: April 17, 2008
FORD:2007-2008 ExpeditionLINCOLN:2007-2008 Navigator
ISSUE:
Some 2007-2008 Expedition and Navigator vehicles equipped with Electronic Automatic Temperature Control (EATC) may exhibit a condition where the blower is inoperative no matter what speed or temp setting or the blower motor is stuck on high speed or off. Cycling the ignition may resume operation. The concern may also occur when using the electrical power point.
ACTION:
Follow the Service Procedure steps to correct the condition.
SERVICE PROCEDURE
Open the glove box and remove Connector C297 from the Heater Blower Controller Module (HBCM).
Remove the right front door scuff plate.
Remove the right side kick panel to gain access to Ground G200.
Cut black/white wire about 8" (20.3 cm) from C297. Strip the end 1/4" (6.3 mm).
Obtain pigtail kit and using the approved splicing methods found in the Wiring Diagram (WD), Cell 5, crimp the butt connector and seal (with shrink tubing) the splice between the 13" (33 cm) pigtail and the black/white wire from C297.
Disconnect the existing 14401 single ground eyelet from G200 and cut existing eyelet from the ground .
Strip 1/4" (6.3 mm) insulation from the 14401 ground wire.
Using the approved splicing methods found in the WD, Cell 5, crimp the butt connector and seal (with shrink tubing) the splice between the 3" (7.6 cm) pigtail and the 14401 wire.
Attach the new interlocked ground eyelet to G200. Torque to 11 ± 1.6 lb-ft (15 ± 2.3 N-m )
Install the right side kick panel and scuff plate.
Replace the HBCM.
Attach C297 to the HBCM.
Close the glove box door.
PART NUMBERPART NAME7L1Z-14S411-ABEyelet Wiring Pigtail Kit7C3Z-19E624-CHeater Blower Controller Module
WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.
OPERATIONDESCRIPTIONTIME080901A2007-2008 Expedition/Navigator: Replace The HBCM, Includes Time To Isolate Ground (Do Not Use With 19700D8, 14200A)0.5 Hr.
DEALER CODING
That Heater blower control modual is the same as the electronic resistor.