Partially drain the cooling system.
Remove the tube gasket from the heater core tubes.
Remove four heater core access cover retaining screws and remove the access cover from the A/C evaporator housing (19850).
Remove A/C electronic blend door actuator.
Slide heater core (18476) and seals from the A/C evaporator housing.
Install the heater core in the A/C evaporator housing with the tube gasket on the outside of the case.
Install A/C electronic blend door actuator as described.
Position the heater core cover on the A/C evaporator housing. Install the four retaining screws.
Refill the cooling system.
before the above follow these instructions first
Section 01-12: Instrument Panel and Console 1997 Thunderbird/Cougar Workshop Manual
REMOVAL AND INSTALLATION Procedure revision date: 05/16/2000
Console Panel, Floor
Open console glove compartment door (06024) to access screws toconsole finish panel (04567).
Remove two screws and lift rear ofconsole finish panel to unsnap snap-in retainers.
Lift rear ofconsole finish panel and slide rearward to release two front locating tabs. Removeconsole finish panel.
With console glove compartment door open, remove console glove compartment mat (047A74).
Remove screws from console glove compartment (06010). Disconnect traction control switch (if equipped).
Remove two screws from bottom of console glove compartment to front floor pan (11135).
Remove two caps and screws (one on either side). Remove floorconsole panel (045A36) (front sides).
Remove two screws retaining front of floorconsole panel toinstrument panel (04320). Disconnect main jumper wire (14A411) and main wiring (14401). Liftconsole panel from vehicle.
Disconnect battery ground cable (14301). Refer to Section 14-01. Wait one minute for the air bag diagnostic monitor (14B056) to deplete the air bag back-up power supply. Refer to Section 01-20B.
Loosen main wiring connector bolt in engine
compartment at LH side of dash panel and separate connectors.
Disconnect radio-to-antenna wiring. refer to Section 15-02, Antenna Removal and Installation
Remove both RH and LH windshield side garnish mouldings (03598).
Remove safety belt anchor bolts. Lift front door scuff plates and remove front door opening weatherstrips (20708) from body flanges.
Remove RH and LH cowl side trim panels (02344). Refer to Section 01-05.
Remove steering column. Refer to Section 11-04, Removal and Installation, Steering Column.
Remove one screw and A/C evaporator register duct (19B680) from under the steering column tube (3514).
Loosen main wiring connector bolt at LH side of steering column opening and separate connectors.
Disconnect and separate brake
pedal wiring connectors.
Open glove compartment (06010) to the stop and unsnap glove compartment door check (06102) from RH side of glove compartment.
Remove three screws retaining bottom of glove compartment door hinge (06050) and glove compartment to the instrument panel (04320).
Remove glove compartment from instrument panel.
Reach through glove compartment opening and disconnect the wiring and vacuum hoses/connector from the A/C evaporator housing (19850).
Disconnect main wiring connectors to air bag diagnostic module.
Remove RH cowl insulation panel and disconnect all connectors from main wiring (14401).
Remove floor console panel (045A36) as described.
NOTE: Protect the instrument panel surface during this procedure.
Using a putty knife or similar tool, insert under the LH or RH corner of the instrument panel upper finish panel (044A90). Pry up on the instrument panel upper finish panel to release one snap clip.
Unsnap the remaining four clips by pulling up by hand, working toward the opposite side of the vehicle.
Remove two nuts retaining LH side of instrument panel to cowl side.
Remove two bolts and one nut retaining the instrument panel to the instrument panel bracket (042C51).
Remove the nut retaining the RH side of the instrument panel to cowl side.
NOTE: The following steps require two technicians.
Remove the six bolts retaining the top of the instrument panel to the dash panel.
Carefully pull instrument panel away from windshield glass (03100) while checking for and disconnecting any remaining wiring connectors. Disengage the antenna wire grommet from the sheet metal and pull the radio antenna lead in cable through the dash panel.
This is not an impossible job but it is a very difficult one to perform, if indoubt spend the money and let a professional do it , it will be worth it in the long run. Hope this helps