The 1997 model year F-Series was introduced with a more aerodynamic design. This new concept shortened the nose of the vehicle and placed the engine farther back in the engine compartment. The engine control module is located within a cavity in the firewall in the engine compartment, between the master cylinder and inner fender. The ECU must be programmed to the vehicle in order to operate. You can order an ECU from most of the chain parts stores. They will require the VIN number for the truck to complete the order. You could also install a computer without programming it, but the truck will have to be towed to the dealership or a repair shop with the capability to program an ECU.
Disconnect the negative battery cable. Remove the ECU electrical connector by unscrewing the connector mounting bolt located in the center with the ratchet, extension and socket. The connector will push out as the bolt is unscrewed. Remove the two bolts retaining the ECU cover. Remove cover and the ECU.
Insert the replacement ECU into the cavity and replace the cover. Replace the cover screws. Insert the connector and thread the retaining bolt into the ECU and tighten it. The bolt will pull the connector into the computer as it's tightened.
Reconnect the negative battery cable. Start the engine and allow it to reach operating temperature. Observe the check engine light. Once the engine is running, the lamp should go out.
