Medium and Heavy Trucks
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Hi my name is***** will be glad to try to help. These trucks are multiplexed wiring and the lighting circuits are programmed into the the chassis and lighting modules. Check the wiring harness and connector pins thoroughly for open circuits or damaged wires between the firewall connector and headlight and if okay between the module, headlight switch ,relays and firewall connector. If okay the next step is to have it plugged into the dealer diagnostic software and reflash/reprogram the software and check for a possible faulty module or switch. Check for chassis module fault codes. Let me know
These trucks have multiple computer modules that control different things. Your lights and switches are all programmed into the chassis module. There is an engine computer ECM, Transmission computer TCM, and also chassis computer SAM module that the lighting circuits and other circuits for the chassis are programmed. Freightliner has exclusive rights on the diagnostic software and program to plug in an test and communicate with the chassis modules. So inspect the wiring and connector pins, bulb, etc. Beyond that you are at the mercy of the dealer.
The lighting circuits on these trucks are not basic lighting circuits. They are all run through a computer.
Beyond a visual inspection of the wiring and connector pins you would need to test continuity of the wire between one end to the other end using an OHM meter. Close to 0 OHMS is a good wire.
Test the wire itself one end to the other yes. To then check if it is getting good ground touch one test meter lead to the wire and the other to a chassis ground and close to 0 Ohms is good
Sounds good. Pleasure to help