l have a 91 Lincoln Towncar and the heater fan only blows on high, l have replaced the whole atc unit and the fan still blows on high someone said bad resistor, someone said bad relay, i've checked under glovebox on inside of car, nothing looking like a relay or resistor, checked all fuses, can only turn off fan by unplugging it under hood, if resistor is on heater case, can you describe what it should look like??

dont no on that car but on other cars l changed look on where the blower motor is you should see a cover with 2 screws with a wire connector pluged into it just unplug it and take out the 2 screws and it pulls out they cost around $20 you can only get them at the dealer just go buy one then you no what you looking for its easy( when u pull it out some are the size of a credit card0

trust me its the resistor

On all Crown Vic/Grand Marquis/Town Car vehicles, the blower motor resistor is located in the engine compartment, at the back side of the engine, beside both of the heater hose connections to the heater core. As stated by the above poster, it is held in place by two 8mm screws. On a vehicle of that age, u may have to purchase the wiring pigtail connector to it as well, since it probably wo not disconnect without breaking of the spade terminal connections to it. Since it is a Town Car, it has the ATC variable resistor, it will look like a mini ''module'' with fins once removed. Hope this helps.