Do you know how to test automotive electrical circuits using a DMM - digital multi-meter ?
Principles of Operation
The headlamp switch is supplied power at all times from the smart junction box (SJB). When the headlamps switch is placed in the headlamps ON position, power is routed to the multifunction switch. Depending on the position of the multifunction switch, power is routed through one of two circuits to the SJB. If the multifunction switch is in the high beam position, power is routed through SJB fuse 12 (15A) and then on to the high beam headlamps. If the multifunction switch is in the low beam position, power is routed through SJB fuses 11 (10A) and 15 (10A) to the LH and RH headlamps, respectively. Power to the multifunction switch is available at all times for the flash-to-pass feature.
Is there B+ voltage at fuse's # 11 & 15 with headlamps on an the multifunction switch is in the low beam position ? If not check for B+ voltage at the multifunction switch . Free wiring diagrams here
http://www.bbbind.com/free-tsb Enter your vehicle info. year , make , model an engine . Under system click on lighting then under subsystem click headlamps . Click the search button then the blue link .
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