KL18 - Operation of the Thunderbird SC SIL

An audible chime will sound under the following conditions:

- Key in "RUN", engine "OFF".

- At high vehicle speeds when engine speed is too high for the transmission gear selected, as follows:

- Greater than 93 mph (4000 rpm) in 3rd gear for automatic transmission.

- Greater than 121 mph (4300 rpm) in 4th gear for manual transmission.

At the same time the Shift Indicator Light (SIL) and chime are activated at high speed, the Powertrain Control Module (PCM) will take action to prevent engine damage from overheating. If coolant gets too hot, or 60 seconds elapse at high speeds, the PCM will shut off three injectors until a safe operating speed is reached or transmission is upshifted to top gear. This PCM action is independent of the SIL and warning chime and will occur regardless of a malfunction in these circuits. Possible causes for SIL always on (other than normal operation):

- SIL circuit to PCM shorted.

- Damaged PCM.

Possible causes for SIL always off (other than normal operation):

- SIL fuse.

- SIL bulb.

- SIL circuit open.

- Damaged PCM.

- Is SIL always on or always off?

Always On: Go to KL23. KL23 - Check SIL Circuit For Short to Ground

Always Off: Go to KL19. KL19 - Check SIL Circuit Fuse