Winter Mode Indicator Lamp/Switch Diagnosis

Circuit Description
The Winter Mode switch has two states of illumination. In normal operation, whenever the ignition switch is on, the snowflake symbol dimly illuminates from a bulb in the switch (the illumination lamp). When Winter Mode is active, an additional lamp (the indicator lamp) within the switch causes the snowflake symbol to illuminate brightly. With the engine running and the transmission in Drive 4, the Winter Mode Indicator Lamp should transition from On to Off or from Off to On with each press of the Winter Mode Selector Switch. The ignition voltage supplies directly to the indicator bulb. The Transmission Control Module (TCM) controls the lamp by grounding the control circuit via an internal solid state device called a driver. The Winter Mode Selector Switch signal circuit is pulled up to B+ within the TCM. The other side of the switch connects to ground. When the switch is on, the signal voltage pulls low. The TCM interprets this signal voltage as a Winter mode request. The Winter mode selection causes the transmission to start in 3rd gear, improving the traction under slippery conditions.

Diagnostic Aids
An intermittent may be a result of the following conditions:
^ Corrosion
^ Mis-routed harness
^ Rubbed through wire insulation
^ Broken wire inside the insulation

Refer to Symptoms for Intermittents. Symptom Related Diagnostic Procedures

Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
6. The Winter Mode switch has 2 states of illumination. In normal operation, whenever the ignition switch is ON, the snowflake symbol dimly illuminates by a bulb in the switch (the illumination lamp). When the Winter Mode is active, an additional lamp (the indicator lamp) within the switch causes the snowflake symbol to illuminate brightly. If the switch illumination lamp is functioning, the feed circuit to the switch is OK.
7. The Winter Mode switch has 2 states of illumination. In normal operation, whenever the ignition switch is ON, the snowflake symbol dimly illuminates by a bulb in the switch (the illumination lamp). When the Winter Mode is active, an additional lamp (the indicator lamp) within the switch causes the snowflake symbol to illuminate brightly. If the switch illumination lamp is functioning, the feed circuit to the switch is OK.