Heat Won't Turn Off!!!
 

I got a '01 Lariat SCrew and the stinkin' heater won't quit pumping! No matter what setting I go to (including A/C), I get an occasional warm blast out the vents - just every minute or so. No noises or anything - just feels like it cycles between the (max) warm and cold setting on the temp control knob. I'm afraid of getting raped at the dealer and I hate dash diving. Anyone out there have an idea what's going on (before I start removing panels and get myself wedged into the dash)!

Pull the temperature adjustment knob off and check to see if the opening where the shaft goes into is not cracked. If it is, buy a new one at the dealer for less than $10.00.

I have just repaired the same problem on my boy's 2001 sporttrack. the problem was the electronic temperature blend door motor. the system on the newer Fords operate by electric and not cable, the temp knob operates a variable resister that sends a signal to the motor that inturn moves the door when the resistance in the motor matche s the knob it stops, or in youre case the resister in the motor has gone bad so it hunts back and fourth.
I was able to gain access to it through the glove box door opening. The motor is a flat white box on top of the heater assembly and has a 5 wire plug in the front it is attached with 3 screw from the top.
If you get a mirror and a flashlight there is a square shaft on top that you can visualize if this is youre problem you should be able to watch that shaft slowly turn a 1/4 turn back and fourth as the temp changes. for a temporary fix you can unplug it when in the desired position and it will stay there. The part is avalable at ford for $48 and change, and although the instruction say to remove the dash it can be done in about one hour without removing the dash. remove the three screws 5/16 heads and gently pry the motor up and out of the shaft. The shaft is keyed so it can only go in one way re install and that should fix it. You can test the control part with an ohm meter It should smmoothly change resistance as the knob is turned I am told that they never go bad it is always the motor. the basic part number you will probly need is 19E616.

I think an '01 Lariat should have EATC; run the self test by pressing FLOOR and OFF on the control head simultaneously, releasing, then pressing AUTO to see if any codes are present. My guess is that the temperature blend door is broken. If it is, you're in for a much bigger fight than replacing the blend door motor.

going on the assumption that I have the same problem. If it is in fact the blend door motor. Would it not temporarily solve the problem by bypassing the heater core so there would be no hot water in the system??? then simply reconnect the heater core when a/c is no longer in season???

Thanks!
 

Thanks for the info guys. Turns out it was the motorized flapper. I was pressed for time and had a local Air-Shop do it to the tune of about $200 - ouch! But it's nice having a cool cab again!