Mercury Forum - Mercury Enthusiasts Forums - 1999 Mercury Sable EATC Problems

I think I'm on the brink of a high repair bill.

I had to replace my 1999 Sable EATC's actuator switch recently. Friendly Ford in Springfield, Missouri, didn't install it right, so I had to return (37 mile round trip) to have it reprogrammed. That seemed to work, but I realize that it's still not right.

If I choose "vent," I get outside air (which is what I want), but, if I don't have the thermostat on 60 degrees, I get heat from the vent. Clearly, if the outside ambient temperature is less than 60 degrees, I'll get heat, even though the "vent" setting is supposed to disable both heating and a/c. I don't think my changing the thermostat in the EATC triggers the heater to come on, but, if it does, it's not mentioned in the owner's manual.

I know the EATC system is not working right, but getting the service department to grasp the point is not the easiest thing and, when it costs ca. $17 in fuel to make a roundtrip to the dealership, it's doubly disheartening.

Does anyone have experience with the pesky EATC system, particularly the system from the early years, i.e., 1999? I know that, if it's electronic, it's an elusive fix. Can someone point me in the right direction? Thanks.