Crown Victoria, Grand Marquis & Town Car
Potentiometer is attached to headlight switch. Unplug potentiometer connector.
Connect self-powered test light between connector circuit No. 57 (Black wire) and switch bracket.
If continuity does not exist, replace potentiometer. If continuity exists, go to next step.
Continuity should exist between connector circuits No. 220 (Dark Blue/Orange wire) and 57 (Black wire) after rotating autolamp control switch knob from OFF to ON position.
Measure resistance between circuits No. 217 (Dark Blue/Orange wire) and No. 57 (Black wire) while rotating switch from OFF position to maximum time delay. Resistance should gradually increase from 2500-4500 ohms (OFF position) to 140,000-260,000 ohms (maximum time delay).
If test results are not as specified, replace potentiometer assembly.
Unplug connector at autolamp relay.
Connect test light between ground and Red/Yellow wire.
Voltage should be present with switch in ON position.
If voltage does not exist, repair Red/Yellow wire to headlight switch and to high-low beam relay
Saturday, September 18th, 2010 AT 8:23 PM