Find the suspect fuse (e.g., TRL MRKR ). Use the small fuse puller (usually clipped inside the cover) or a pair of needle-nose pliers. Visually inspect the metal strip inside. If it’s broken, it’s blown. For accuracy, touch a test light to both small metal tabs on top of the fuse.
Squeeze the latches and lift the cover. Turn the cover over to read the fuse diagram. trailer light fuse freightliner cascadia
Open the driver’s side battery box door. You will see a black plastic box with a latch—that is the PDM (Power Distribution Module). Find the suspect fuse (e
Insert a new fuse of the exact same amperage . Never replace a 10A fuse with a 20A fuse to "make it work." You will melt the wiring in your trailer cord. If it’s broken, it’s blown
If you’ve recently had suspension work or a wreck repair, a wire harness may be rubbing against the frame rail near the rear of the cab.
Turn off the ignition and remove the key. Wait 30 seconds for the ECU modules to fully power down.
