Starting From Cold In AUTO Working Mode

Conditions are appropriate for cold start when outside temperature is 5° C (9° F) or more below the preselected temperature and the Automatic Climate Control (ACC) control module has calculated that a blended air temperature greater than +80° C (176° F) is required.

Air distribution starts in defrost position, and then goes to defrost/floor position as blended air temperature increases.
(See table)

When starting from cold, fan current is also dependent on blended air temperature

Year models 1985-89
The system selects defroster position and fan speed 2 to begin with. The electrically heated rear window is switched on. When incoming air temperature reaches about 50° C (122° F), as measured by the blended air temperature sensor, air starts to be directed to the floor and fan speed is raised to 2.5 and then slows as selected temperature is achieved.

Year models 1990-94
Air distribution damper, cold start positions

Blended air temperature damper
below +35° C (95° F) "defrost" position
+35° C - +50° C Off "defrost" on
(95 - 122° F) "heat" position
above +50° C (122° F) Normal operation







Year models 1990-94
Ventilation fan, speed when starting from cold

Blended air temperature
below +35° C (95° F) Current about 4.5 A
+35° C - +50° C Current about
(95 - 122° F) 4.5- 6.4 A
+50° C - +55° C Current about
(122 - 131° F) 6.4-12 A

As soon as the value calculated by the Automatic Climate Control (ACC) unit for blended air temperature drops below +80° C (176° F), but no less than 1 minute after starting, a switch over to normal operation takes place for both the air distribution damper and fan speed.

Year model 1995-
When starting from cold, there is a pre-programmed maximum fan speed.
Fan speed varies within the shaded area on the diagram above.
Even if the ACC control module has calculated that a higher fan speed is required, speed will never exceed the preprogrammed maximum speed, in graph. This maximum speed can be adjusted using the ISAT scan tool