Normal Operation
WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
The driver temperature control seat module communicates with the diagnostic tool through the universal asynchronous receiver-transmitter (UART)-based protocol (UBP) communications network circuit 4-HC21 (GY/OG). If circuit 4-HC21 (GY/OG) becomes open or shorted to ground, communications to that module is not possible. Check circuit 4-HC21 (GY/OG) between the temperature control seat module and the data link connector (DLC) C251. The total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is either an open in circuit 4-HC21 (GY/OG), damage to the DLC C251, damage to the driver temperature control seat module C3031a, or a problem with in-line C213, in-line C315 or joint connector No. 1 C261.