To troubleshoot, you need to consult your owner's manual. It will have a fuse diagram showing all the fuses and relays, and what circuits they protect. Look for fuses related to the following (these might be labeled differently in your manual):
* Power locks: This is the most likely candidate. A blown fuse in the power lock circuit will prevent the keyless entry from unlocking or locking the doors.
* Body control module (BCM): The BCM controls many vehicle functions, including the keyless entry system. A problem with the BCM itself could also be at fault, but you'd typically start by checking fuses.
* Remote keyless entry system: Some vehicles have a dedicated fuse, but it's less common.
Steps to check:
1. Consult your owner's manual: This is the most important step. Locate the fuse box diagrams (there's usually one under the hood and one inside the cabin).
2. Identify potential fuses: Based on the above suggestions (power locks, BCM, remote keyless entry, if listed), check the corresponding fuses with a test light or multimeter.
3. Replace any blown fuses: If you find a blown fuse, replace it with one of the same amperage rating. If the fuse blows immediately after replacement, there's a short circuit somewhere in the system and you should take it to a mechanic.
4. Check for other problems: If all the fuses are good, the problem could be with the key fob battery, the key fob itself, the BCM, or the door lock actuators.
Important Note: Working with car electrical systems can be dangerous. If you are not comfortable working with electricity, take your truck to a qualified mechanic. Improperly handling fuses or other electrical components can lead to damage to your vehicle or personal injury.
