Sounds like a Evap temp sensor going open to me. The 140 is the only one with a override for the center vent. (thats the blue and red buttons on the vent.) With the blue button pressed and ac set if the evap temp sensor goes open momentarly the SIDE vents will go full hot. The side vents perate the "dual zone" climate control by adjusting indepently of the center. Confused yet? It gets better. They never decided exactly where to put the sensor. 95% of them are in the side of the case below the expansion valve plumbing (which you cant see from inside but its over the gas pedal) and all but hidden from view by the wiring and various other odds and ends in there.



Joe

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Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
919-881-0364