Medium and Heavy Trucks
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Hi ***** name is***** will be glad to try to help. Check for power in and out of the Ignition switch in all positions and wiggle the key to see if there is any loss of power or continuity from worn contacts inside the switch while doing so for accessory or on position out of the switch. If okay check your relays and harness and connections in the connectors etc. for damage, shorts or corrosion. Also let me know if you have any fault codes logged in the body controller that will help isolate the source of the problem. Let me know
Click on this link for the schematics to help in identifying the Main power and ignition circuits.