Pinpoint Test C: The Climate Control Illumination Is Inoperative: Expedition

The instrument panel dimmer switch generates a variable pulse width modulated (PWM) voltage which is distributed to the electronic automatic temperature control (EATC), rear auxiliary climate control, and the manual climate control on circuit 19 (LB/RD). Voltage is distributed to the front climate control through circuit 875 (BK/LB). The EATC is grounded through circuit 875 (BK/LB). The front and rear auxiliary climate controls and the manual climate control are grounded through circuit 57 (BK).